Elevated low-density lipoprotein cholesterol is more likely to increase the risk of cardiovascular in men than in women
Men generally develop CVD at a younger age and have a higher risk of coronary heart disease (CHD) than women.
It appears that men's coping with stressful events may be less adaptive physiologically, behaviorally, and emotionally, contributing to their increased risk for CHD.
CVD is the leading cause of death worldwide, yet important differences exist between men and women
During a woman's fertile age, estrogens have been found to exert beneficial effects on the cardiovascular system (CVS), which often protects women from atherosclerosis during this time.
To look more about cardiovascular disease click here
brainly.com/question/1323797
#SPJ4
what enzyme can proof-read the dna molecule, minimizing the mistakes made during the process of dna replication?
The DNA polymerase enzyme's capacity to proofread the DNA molecule helps to decrease DNA replication mistakes.
Fortunately, cells have developed extremely complex mechanisms to correct most of those errors, but not all of them. While some errors are fixed following replication in a stage called mismatch repair, others are fixed while replication is still happening in a stage called proofreading. Replication is impeded when an erroneous nucleotide is added to the developing strand because the exposed 3′-OH group is in the wrong location. DNA polymerase enzymes notice this during proofreading and swap out the erroneous nucleotide to keep replication going. Even if 99 percent of mistakes may be corrected by proofreading, accurate cell reproduction is still not possible.
Learn more about DNA polymerase at
https://brainly.com/question/30196920?referrer=searchResults
#SPJ4
Light energy travels ______________km where plants capture the light energy and convert it to _______________ energy.
The Biosphere and other photosynthetic organic entities catch light energy that has voyaged 150 million km from the sun and convert it to substance energy that is put away in sugar and other natural particles. This transformation interaction is called photosynthesis.
Photosynthesis is the cycle by which plants use daylight, water, and carbon dioxide to make oxygen and energy as sugar.
The light-reliant responses utilize light energy to make two particles required for the following phase of photosynthesis: the energy stockpiling atom ATP and the diminished electron transporter NADPH. In plants, the light responses happen in the thylakoid layers of organelles called chloroplasts.
Photosynthesis is the synthetic cycle by which plants convert light energy (from the Sun) into substance energy as natural food particles like glucose. The photosynthetic responses happen in the chloroplasts, a particular organelle in plant cells.
To learn more about photosynthesis here
https://brainly.com/question/29764662
#SPJ4
in what tissues, cells and organ does ependymoma first start
It begins in the spinal cord or brain
Results from a wide-range of climate model simulations suggest that the Earth's average surface temperature could be between 1. 1 and 5. 4°C warmer in 2100 than it was in 2015. Which best summarizes this information:
By 2100, the global average annual temperature will increase more than 1. 1 and less than 5. 4°C.
By 2100, the global average annual temperature will decrease more than 1. 1°C.
By 2100, the global average annual temperature will increase more than 5. 4°C.
By 2100, the global average annual temperature will decrease more than 1. 1 and less than 5. 4°C
Results from various climate model simulations suggest that the Global average temperature in 2100 could be 1.1 to 5.4 °C (2 to 9.7 °F) higher than today. The main cause of this temperature rise is "greenhouse gases" that trap carbon dioxide and other heat produced by human activity.
Global average temperature is projected to increase by 2°F to 11.5°F by 2100, depending on future greenhouse gas emission levels and the results of various climate models.
Fossil fuels release carbon dioxide, a greenhouse gas that can increase the average temperature of the earth. In a high-emissions scenario, global temperatures could rise by 4.4 degrees by 2100, says the IPCC, with potentially catastrophic consequences.
For more information on Global average temperature , visit :
https://brainly.com/question/19695449
#SPJ4
What are the 5 chromosome mutations?
The 5 chromosome mutations are given as , duplication, deletions, insertions , inversions, translocation.
1. Duplication: The multiple copies of a chromosome that occur during the duplication process.
2. Deletions - When a nucleotide is removed, the mRNA codons change (the nitrogen bases of a DNA). This will change the makeup of amino acids.
3. Insertions – An insertion is the addition of a new nucleotide.
4. Chromosomal inversions happen when a chromosome fragment breaks off and reattaches in the opposite direction to the same spot.
5. Translocation: This is the splitting in half and moving of two chromosomes.
To know more about chromosome
https://brainly.com/question/29873651
#SPJ4
Using your prior knowledge in the background information about the Asian ladybug, fill in each of the
A scientist is investigating the possibility that two traits in a particular plant are determined by genes that are on the same chromosome. The scientist crossed a plant that is homozygous dominant for both traits with a plant that is homozygous recessive for both traits. The heterozygous offspring in the Fl generation were then crossed with a plant that is homozygous recessive for both traits. The results expected if the genes independently assort and the observed results are presented in the table. Phenotype Expected Number in F2 Observed Number in F2 25 17 Long stems, white flowers Short stems, red flowers 25 19 Long stems, red flowers 25 31 25 33 Short stems, white flowers Total number of plants 100 100 Which of the following critical values should the scientist use for the chi-square analysis of the data? a. 3.00 b. 3.84 c. 7.81 d. 8.00
The critical value the scientist should use for the chi-square analysis of the data is b. 3.84.
THE CHI-SQUARE ANALYSIS OF THE DATAThe chi-square test is a statistical test used to determine whether there is a significant difference between the observed and expected frequencies in a contingency table. In this case, the scientist is investigating whether two traits in a plant, long stems and white flowers, are determined by genes that are on the same chromosome. The scientist has conducted a genetic cross between plants that are homozygous dominant and homozygous recessive for both traits, and has obtained a sample of 100 plants in the F2 generation. The scientist has then tabulated the observed and expected frequencies of the four possible phenotypes (long stems, white flowers; short stems, red flowers; long stems, red flowers; short stems, white flowers) in the F2 generation.
The chi-square test is used to determine whether there is a significant difference between the observed and expected frequencies in the table. The calculated chi-square value is compared to a critical value from a chi-square distribution table with 3 degrees of freedom and a significance level of 0.05. The degrees of freedom for a chi-square test are equal to the number of categories in the table minus 1. In this case, there are 4 categories (phenotypes) in the table, so the degrees of freedom are 3.
The critical value for this test is 3.84. If the calculated chi-square value is less than 3.84, the scientist would conclude that there is no significant difference between the observed and expected frequencies and thus the genes independently assort, meaning that the genes are located on different chromosomes. On the other hand, if the calculated chi-square value is greater than 3.84, the scientist would conclude that there is a significant difference between the observed and expected frequencies and thus the genes are located on the same chromosome.
Learn more about the chi-square here:
https://brainly.com/question/14082240
#SPJ4
After a cell was treated with a certain chemical, the ribosomes stopped functioning. Which cell activity was immediately affected by this change in ribosome function
The ribosomes ceased working when a cell was exposed to a certain substance. Protein synthesis is the first cell activity influenced by this alteration in ribosome function.
As a result, B is the right answer.
Cells are the fundamental structural components of all living things. Ribosomes are specialized structures found inside cells that manufacture proteins. A eukaryotic cell's protein production is comprised of two processes: transcription and translation.
The transcription process occurs in the nucleus, where information from a DNA strand is transcribed into a single-stranded messenger RNA (mRNA) molecule by the RNA polymerase enzyme.
During the termination of transcription, the completed mRNA strand detaches from DNA, exits the nucleus, and enters a cytoplasmic ribosome. Translation happens at the ribosome, where the genetic code in mRNA is read and protein is made.
Cells require these proteins to accomplish vital processes such as mending cellular damage, maintaining cellular structure, producing hormones, and dividing cells.
Learn more about to ribosomes ;
https://brainly.com/question/241631
#SPJ4
Full Question ;
After a cell was treated with a certain chemical, the
ribosomes stopped functioning. Which cell activity was
immediately affected by this change in ribosome function?
A) intracellular transport
B) protein synthesis
C) aerobic respiration
D) excretion of metabolic wastes
What are the factors that affect genetic variation with examples?
The factors that affect genetic variation are genetic mutations, gene flow, genetic drift and random mating.
Genetic variations are the changes in the genetic sequence of the DNA. These genetic variations are important as they allow the living beings to evolve and survive. There are certain factors which affect genetic variation and they are genetic mutations, gene flow, genetic drift and random mating.
A genetic mutation is basically a change in the DNA sequence of a particular gene which causes a different product to form. It is able to create a permanent change to that particular gene's DNA sequence. Gene flow can be defined as the movement of genes in and out of a specific population. Genetic drift is the change in allelic frequency by chance. Random mating is the mating of individuals which is not dictated by any social or genetic preference.
To learn more about genetic variations here
https://brainly.com/question/848479
#SPJ4
The cardiac muscle receives its supply of oxygenated blood by which of the following mechanisms?
A. Coronary veins that branch off the pulmonary vein
B. The cardiac conduction system
C. The carotid and femoral arteries
D. Coronary arteries that branch off the aorta
The cardiac muscle receives its supply of oxygenated blood by D.) coronary arteries that branch off the aorta.
How does cardiac muscles receives its supply of oxygenated blood?The cardiac muscle receives its supply of oxygenated blood by the coronary arteries that branch off of the aorta.
Coronary arteries supply blood to heart muscles. Like all other tissues in body, the heart muscle needs oxygen-rich blood to function. And, oxygen-depleted blood must be carried away. Coronary arteries wrap around the outside of heart.
4 main coronary arteries are the right coronary artery, left main coronary, left anterior descending and the left circumflex artery.
To know more about coronary arteries, refer
https://brainly.com/question/8329409
#SPJ1
Many lethal genetic disorders such as CF, Huntington’s, sickle cell anemia, Tay Sach’s, etc., persist in the human genome.
How have these genes survived so many millennia of evolution (why didn’t they die out)?
These genes survived so many millennia of evolution because most of the genetic disorders are caused due to mutation in genome.
What is Mutation?This is referred to as an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA by different factors.
The factors which cause mutation in individuals are exposure to mutagens or a viral infection which may be due to the high increase in the technology available in the environment in which they live and operate
These genes such as those which cause disorders such as Huntington’s, sickle cell anemia, Tay Sach’s, etc survived so many millennia of evolution because there is still the cause being present in our everyday world which is therefore the reason why it was chosen as the correct choice.
Read moire about Mutation here https://brainly.com/question/17031191
#SPJ1
Why do whales need oxygen?
Whales need oxygen for respiration processes because they do not have gills, and whales are unable to breathe oxygen that is dissolved in water.
The lack of gills, which prevent whales from breathing oxygen dissolved in water, is the most obvious distinction between whales and other fish. Instead, they have lungs, which means that whenever they want to breathe air, they have to come to the surface.
They can stay underwater for hours at a time because they have a very efficient respiratory system that allows their lungs to get the most out of each breath. To put things in perspective, when we are at rest, humans breathe about 12 to 20 times per minute, but they only take in 5% of the oxygen in a single breath. This is in contrast to a whale, which can absorb up to 90% of the oxygen it breathes. This indicates that a whale takes in significantly more oxygen in a single breath than a human does.
Know more about Respiration here: https://brainly.com/question/12605249
#SPJ4
How many total permanent teeth should an adult have, assuming none have been lost or removed? -8 -16 -20 -32
Answer:
The correct answer is 32 teeth.
Explanation:
Hope it helped:)
How might a mutation affect the active site of an enzyme?
A mutation that occurs in a region of the DNA that codes for an amino acid sequence found in the active site of an enzyme can change the folded morphology of the active site and its affinity for its substrate.
Large regions of DNA can replicate when there is a mutation, usually as a result of genetic recombination. Animal genomes duplicate tens to hundreds of genes per million years, creating a significant genetic resource for the generation of new genes. The bulk of genes can be classified into bigger gene families that share an ancestor using sequence homology. The procedures that most typically result in novel genes are the duplication and mutation of an ancestral gene or the recombination of segments from several genes to create new combinations with novel functions. When connected, protein domains work as modules, each with a distinct purpose, to create genes that code for new proteins with unusual features.
To learn more about mutation click on the given link: https://brainly.com/question/17130462
#SPJ4
Kelp forests are a very important ecosystem in marine waters by supporting important biodiversity. These kelp forests are threatened by all of the following except _____.
Kelp forests are a very important ecosystem in marine waters by supporting important biodiversity. These kelp forests are threatened by all of the following except presence of large predators.
Kelp forests are an incredibly important marine ecosystem that provide a variety of benefits to the surrounding environment. They are a prime source of habitat and food for a large variety of species, including fish, invertebrates, and even certain species of seabirds. In addition, kelp forests also act as a type of buffer, protecting coasts from erosion and providing habitat for juvenile fish, which helps to maintain coastal fish populations. Unfortunately, kelp forests are threatened by many factors, including overfishing, pollution, and climate change.
The one factor that does not threaten kelp forests is the presence of large predators. While large predators can have a significant impact on the overall structure of a kelp forest, they are not directly responsible for the decline and destruction of kelp forests. For example, while sea otters, seals, and sea lions can have a significant impact on kelp forests by over-browsing, they are not the cause of the decline in kelp forests.
Learn more about climate change at :https://brainly.com/question/28779953
#SPJ4
Classifying and Exploring Life Lesson 1. Characteristics of Life Lesson 2. Classifying Organisms Lesson 3. Identifying a Beetle Lesson 4. Exploring Life Lesson 5. Constructing a Dichotomous Key
There appear to be five different lesson topics related to studying life, its characteristics, and to classify and identify different organisms.
"Characteristics of Life," would likely cover the basic characteristics that all living things share, such as the ability to grow, reproduce, and respond to their environment.
"Classifying Organisms," would likely cover how scientists group and classify living things into different categories based on their characteristics, such as the use of taxonomy and the classification system proposed by Carl Linnaeus.
"Identifying a Beetle," would likely focus on teaching students how to identify different species of beetles by their physical characteristics, such as size, shape, and coloration.
"Exploring Life," would likely focus on introducing students to the diversity of life on Earth and the different ways in which living things interact with each other and their environment.
"Constructing a Dichotomous Key," would likely teach students how to use a dichotomous key, which is a tool that helps identify different species by asking a series of questions and narrowing down the options based on the answers.
To know more about classification visit :
https://brainly.com/question/1620211
#SPJ4
Only about _____ of genes are different from one person to the next. Those that are different are called _____.
The correct answer is A; 1%, alleles, A gene mutation is a change that occurs in one or more genes (myoo-TAY-shun). Certain genetic mutations can cause genetic disorders or illnesses.
The human genome is substantially same in all individuals. There are, however, variations across the genome. This genetic variety accounts for around 0.001% of each individual's DNA and results in differences in appearance and health. People who are closely related share more DNA.
There are genes that are dominant and recessive. The most common interaction between alleles is a dominant/recessive relationship. When one allele of a gene effectively overrules the other (recessive) allele, the dominant allele is said to exist. Correlations between dominant and recessive genes can be seen in eye color and blood type.
Learn more about to gene
https://brainly.com/question/8832859
#SPJ4
Full Question ;
Only about _____ of genes are different from one person to the next. Those that are different are called _____.
A) 1%, alleles
B) 20%, alleles
C) 1%, traits
D) 20%, traits
The element phosphate can be found in which macromolecule(s):
O Protein
O Lipids
O Carbohydrates
O Nucleic Acids
O All of the above
O Proteins and Nucleic Acids only
O Carbohydrates and lipids only
The element phosphate can be found in nucleic acids.
Nucleic acids are macromolecules that are made up of nucleotides, which are the building blocks of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Each nucleotide consists of a sugar (either deoxyribose in DNA or ribose in RNA), a nitrogenous base (adenine, guanine, cytosine, or thymine in DNA; adenine, guanine, cytosine, or uracil in RNA), and a phosphate group. The phosphate group is an important component of the nucleotide and plays a key role in the structure and function of nucleic acids.
Hope This Helps You!
Which substances are neuropeptides that inhibit pain impulse transmission in the brain and spinal cord
The most important of them is beta-endorphin, which, in addition to significantly lowering pain (its analgesic potency is many times that of morphine), is the opioid peptide that induces the most pleasure.
GABA, a neurotransmitter, also plays a role in central pain regulation by enhancing descending inhibition of spinal nociceptive neurons.
Neuropeptides are a broad category of chemically unique compounds that are found in and emitted by various sensory neurons. They play a role in the development, transmission, modulation, and perception of all forms of pain (physiological, neuropathic and inflammatory).
Neuropeptide Y (NPY) is a pain modulator that is generated in the brain. NPY receptors are found in the trigeminal ganglia and the trigeminal nucleus caudalis, implying an involvement in pain.
Learn more about to Neuropeptides
https://brainly.com/question/13769834
#SPJ4
Label the following blood pressure readings as hypotensive, normal, pre-hypertensive, or hypertensive.
The following blood pressure readings are :
100/70 - Normal
150/95 - Hypertensive
130/85 - Pre-hypertensive
80/50 - Hypotensive
High blood pressure is nothing but high blood pressure and is a serious condition because it forces the heart to work harder to pump blood throughout the body and can increase the risk of heart attack, stroke and kidney failure if left untreated. Likewise, low blood pressure is hypotension.
Normal blood pressure varies from person to person, but the American Heart Association recommends a target blood pressure of less than 120 mm Hg systolic and less than 80 mm Hg diastolic. Stage 1 hypertension is when a person has a systolic blood pressure of 130-139 or a diastolic blood pressure of 80-89.
For more information on blood pressure , visit :
https://brainly.com/question/19479857
#SPJ4
Complete question :
Label the following blood pressure readings as hypotensive, normal, pre-hypertensive, or hypertensive.
100/70, 150/95, 130/85, 80/50
What is the first and the most important step in the resuscitation of this newborn?
The single most crucial and efficient phase in cardiopulmonary resuscitation of a critically ill newborn is lung ventilation. The newborn should be placed under a radiant heat source to offer warmth. The baby should then be dried off, their airway should be cleared with a bulb syringe or suction catheter if necessary, and their breathing should be stimulated.
Rescuers should make sure that aided ventilation is being administered as optimally as possible before beginning chest compressions because ventilation is the most effective intervention in neonatal resuscitation and because chest compressions are likely to compete with good ventilation. Thus successful resuscitation depends on efficient ventilation. One cannot always foresee or forecast the necessity for neonatal resuscitation at birth.
To know more about newborns please visit
https://brainly.com/question/29489266
#SPJ4
Use this sentence: A fault cuts across several layers of rock. Which conclusion can be made?
A. The fault is younger than the layers of rock based on the law of inclusion.
B. The fault is younger than the layers of rock based on the law of crosscutting. C. The fault is older than the layers of rock based on the law of inclusion.
D. The fault is older than the layers of rock based on the law of crosscutting.
Answer:
I think its B
Explanation:
I DK if I'm right bc I'm stuck on the same question
just get one wrong and if you get everything else right, it won't matter at all.
Please help I don't understand them
The first reaction in the image is hydrolysis reaction and the second one is condensation reaction.
What is chemical reaction?The process of changing one group of chemical compounds into another is referred to as a chemical reaction.
A condensation reaction is a kind of chemical reaction in organic chemistry where two molecules join to produce one molecule, typically with the loss of a minor molecule like water.
The process is also referred to as a dehydration synthesis if water is lost during it.
The hydrolysis reaction is the reverse of a condensation reaction and involves two molecules (often H2O) reacting to form two distinct molecules.
Hydrophobic compounds can't dissolve or mix with water. Hydrophobic substances are those that naturally repel water, resulting in the formation of droplets.
Thus, as in the first reaction, water molecule is used to break the bond so it is hydrolysis, as well as the removal of water molecule in second reaction shows condensation reaction.
For more details regarding chemical reaction, visit:
https://brainly.com/question/29039149
#SPJ1
What is the best evidence we have for evolution ?
The continuity of the fossil record from ancient to contemporary times may be the strongest fossil evidence supporting evolution.
We don't find things like mammals in strata from the Devonian, the age of fishes, or human fossils alongside dinosaur remains anywhere on Earth. Evolution that is, common descent, gradualism, species diversification, and natural selection are the five hypotheses that Darwin united. A theory is an explanation for how a natural phenomenon functions that has undergone extensive testing through observations and experiments intended to establish the validity of the explanation. In this context, evolution might be considered both reality and a theory. The fact that creatures have altered or evolved over the course of Earth's history is undeniable.
Learn more about Evolution here:
https://brainly.com/question/6111443
#SPJ4
If a large amount of lactate is being produced, what is the best conclusion that you can make about the rate (how fast) and amount (magnitude) of energy needed
Lactate production increase when the energy (ATP) needed is high but oxygen levels are low. To fulfill this demand, the rate of lactic acid metabolism must be increased as well.
Lactic acid metabolismLactate as waste is the product of fermentation or anaerobic respiration. Anaerobic respiration is categorized into alcoholic metabolism and lactic acid metabolism.
Lactic acid metabolism itself is the metabolic process that produces a little energy. In this metabolism, besides yield 2 ATP also produces lactate per glucose. The process happens in muscle cells as not being supplied with enough oxygen. Times when our body's oxygen level might drop is during intense exercise, whereas, at this condition the demand for ATP is increased.
Thus, to fulfill a lot of energy (ATP) needed, particularly as exercising, the rate of lactic acid metabolism must do faster although it could cause lactate production will also increase.
Learn more about lactic acid metabolism by clicking this link :
https://brainly.com/question/28528920
#SPJ4
How does carbon dioxide affect whales?
Whales accumulate carbon in their bodies during their long lifespans. When they die, they sink to the bottom of the ocean. Each large whale binds an average of 33 tons of carbon dioxide and removes this carbon from the atmosphere over centuries. Trees, on the other hand, only absorb up to 48 pounds of CO2 per year.
Rapid global warming has led to habitat loss for whales and dolphins, increasing competition for fewer and fewer prey species. It affects the timing and extent of migration, distribution and even fertility.
Scientists call large whales "ecosystem engineers." Research shows that whales cycle nutrients in the oceans, help produce the oxygen we breathe, and play an important role in mitigating greenhouse gases. Whales are not only amazing, they are breathtaking.
For more information on , visit :
https://brainly.com/question/14803609
#SPJ4
The relative movements of Earth, the Moon, and the Sun create patterns of change we observe.
A complete and accurate model for explaining the phases of the Moon visible on Earth requires which of the following?
Select all that are needed.
- sun
-earth
- moon
The Sun constantly illuminates one-half of the Moon, but the amount of this half that we can view from Earth determines the phase that we observe. the phases of the Moon visible on Earth requires the sun, earth, and moon.
What are the phases of the Moon?Only the "night" side of the Moon is visible during the new moon. if there is a full moon, the Moon will rise just before dusk.
About two weeks pass between the new moon and the full moon. At the new moon, the luminous portion of the Moon that faces the Sun is complete.
Therefore, the many moon forms that are visible from Earth are referred to as phases of the moon.
Learn more about Moon, here:
https://brainly.com/question/3287763
#SPJ1
What is weight of 100 seeds called?
The weight of 100 seeds is known by the name Hundred Seed Weight (HSW).
Seed is the fertilized ovule that represents the undeveloped part of the plant. It consists of all the essential enzymes and food reserves required for its growth and development into a fully grown plant. The seeds can remain in dormant stage for a very long period of time.
HSW gives the yield of the plant and is also an indicator of the inheritance of the quantitative characteristics and how the inheritance is affected by the genotype and environmental factors. Large seeds impact the yield of the plant positively.
To know more about seeds, here
brainly.com/question/18261734
#SPJ4
Please Help Me Outttt
The function of a specific enzyme is most directly influenced by its 'physical shape'.
What do you mean by enzymes?
Enzymes are basically proteins that act as catalysts, speeding up chemical reactions in the body. They are essential for life and are involved in many of the body's processes, such as digestion, metabolism, and energy production.
The physical shape of an enzyme is determined by its specific sequence of amino acids, which forms its active site. This active site is the part of the enzyme that binds to substrates and facilitates chemical reactions. The physical shape of an enzyme determines what substrates it can recognize and bind to, which in turn influences the rate at which the reaction occurs. Therefore, the physical shape of an enzyme directly affects its function.
Hence, Option B is correct.
To know more about enzymes,
https://brainly.com/question/14577353
#SPJ1
22: What are the reactants (substances needed) for photosynthesis.
Plants require three elements in order to perform photosynthesis: carbon dioxide, water, and sunlight.
What are the two end products and three reactants of photosynthesis?According to the chemical equation for photosynthesis, the reactants (carbon dioxide, water, and sunlight) result in the production of glucose and oxygen gas as two products. The complete mechanism of photosynthesis is represented by a single chemical equation.
Is photosynthesis a reaction of what kind?A reaction that is endothermic is photosynthesis. This indicates that without energy, it cannot happen (from the Sun). Chlorophyll, a green pigment found in leaves, absorbs the needed light.
To know more about photosynthesis visit:-
https://brainly.com/question/29764662
#SPJ1