Biology College

Question 21
As human migrated away from the equator, what may have been a selective
pressure against more melanin?
Cold weather and too much body hair
Lower UV radiation and more DNA mutations
Higher UV radiation resulting in more vitamin D synthesis
Lower UV radiation resulting in less vitamin D synthesis

Answers

Answer 1

Answer:

Higher UV radiation resulting in more vitamin D synthesis.

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Thanks!

Explanation:

Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years.

Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years.During exposure to sunlight 7-dehydrocholesterol in the skin absorbs UV B radiation and is converted to previtamin D3 which in turn isomerizes into vitamin D3.

Related Questions

What controls the cell cycle at key checkpoints?

Answers

Answer:

Two groups of proteins called cyclins and cyclin-dependent kinases (Cdks), are responsible for the progress of the cell through the various checkpoints. The levels of the four cyclin proteins fluctuate throughout the cell cycle in a predictable pattern

Explanation:

I hope this helped you!

When did the reign of terror end ?

Answers

Answer:

July 28th, 1794

Answer:July 28, 1794

Explanation:

Hope it helps

Kubusse. Fig. A Fig. B Fig. C ANSWER: ANTWOORD Choose: / Kies Figure A, B or C/ Figuur A, B or C. QUESTION / VRAAG 2.1 What Figure has the greatest volume? Watter figuur het die grootste volume? 2.2. What figure has the greatest surface area? Watter figuur het die grootste oppervlakte? 2.3 2.4 What figure has the greatest surface area : volume ratio? Watter figuur het die grootste oppervlakte : volume verhouding? If each cube represents a cell. What figure will be the most efficient of transporting materials into and out of the cell? Indien elke kubus 'n sel verteenwoordig, watter figuur sal die meest efektiefste wees om stowwe in en uit die sel te vervoer? ( 4)

Answers

Answer:

Explanation:

make me brainless

I have two questions .

Earth Science

Answers

Answer:

here's some thoughts

Explanation:

Glaciers cut through rock and deposit the sediments as they melt.

In Connecticut, Long Island Sound was created by glaciers. Glaciers created a natural barrier between the ocean and the land. Almost like a moat protecting a castle.

There are many large boulders in cities around Connecticut that were left behind after the ice melted away. The Connecticut River Valley was cut by a glacier.

please help biology!!!

Answers

Looks like the answer is d because there are 3 big T’s which are for short and one square with just the smaller t’s which represents long tails

Englo
Unit Test
Ur Test Active
2
8
TIME REMAINING
01:53:24
Sopria was stucying with Maalik about the layers of the Earth. They were given several different statements about the
Which statement about the layers would they identify as correct?
The outer core is less than 70 km in thickness.
The crust assists informing Earth's magnetic field.
The mantie is derser than the crust
O Pressure increases when moving from the core to the crust.

Answers

Answer:

I think the answer is B

Explanation:

Sorry If I got it wrong -w-

Answer:

its b

Explanation:

Based on this information, what can you conclude about tissues? A. All tissues in the body have similar functions. B. All tissues band together to form cells. C. Each type of tissue has a different function. D. Some tissues are more important than others.

Answers

Answer: Each kind of tissue has a different function

Explanation:

Our tissues are divided into four types: epithelial, connective, muscular, and nervous. The structure of each type of tissue differs from one another, which determines its function.

collagen is living or nonliving?

Answers

Non living . As it doesn’t contain life

Answer:

The answer is nonliving.

what are the two basic parts of a plant

Answers

the shoot and root systems, I hope this answer finds you well :)

Answer:

the shoot and root systems

Explanation:

A plant is made up of two basic parts, the shoot and root systems. Within each system you will find more complex anatomy. On the shoot system, the stem, leaves, flowers, and fruit can be seen

Which one of the following statements is TRUE regarding bone?

Answers

Answer:

Where are the statements my friend so i can help you?????

Explanation:

Why would competition among individuals within a deer population increase during a winter season?
A. Many plants die and less vegetation is available.
B. The winter season has produced an abundance of food.
C. Many individual deer have emigrated.
D. The population has suffered a crash as a result of attack by predators.

Answers

Answer:

A. many plants die and less vegetation is available

Explanation:

Therefore, they have to increase competition for scarcer resources.

What is the process that some plants used to flower at the same time every year?

Answers

Flowering plants grow from seeds
The embryo inside the seed starts to grow into a seedling. Roots grow down to anchor the plant in the ground. Roots also take up water and nutrients and store food. A shoot grows skywards and develops into a stem that carries water and nutrients from the roots to the rest of the plant

Hope this helps x)

Answer:

Photoperiodism

Explanation:

What type of chemical reactions only occur if there is an input of energy?

Answers

Answer:

Synthesis reactions

Explanation:

"Synthesis reactions bond reactants together, a process that requires energy, whereas decomposition reactions break the bonds within a reactant and thereby release energy." :)

Oxygen has 17 known isotopes. The atomic number of oxygen -16 is 8. What can you tell me with this information about isotopes of oxygen?

Answers

Answer:

slwug

Explanation:

jrjdhdhdhdhdbdhdhdhdhdhdhdhd

Which of the following correctly shows a prairie food chain?
grass, grasshopper, lizard, hawk
hawk, grasshopper, lizard, grass
snake, grasshopper, hawk, grass
grasshopper, grass, snake, hawk

Answers

The first one does.

Answer:

A - Grass, Grasshopper, Lizard, and Hawk

Explanation:

Grass will start first because it is the producer, then Grasshopper, Lizard and Hawk. It is like going from smallest to biggest.

A biology student is writing a research paper about different bear species.
He begins by writing that all bears belong to the Class Mammalia, Order
Carnivora, and the Family Ursidae. Which scientific aspect of bears is he
writing about?

1.Embryology

2.Comparative Anatomy

3.Taxonomy

4.Molecular Biology

Answers

The scientific aspect of the bears he is writing about is taxonomy.

What is the concept of taxonomy?

Taxonomy is, by

DefinitionClassificationSystematic.

The rescue of taxonomy in information systems considers the systematic unit (taxon) no longer family, genus, species, but concepts. Here, the classes are presented in a logical order, also supported by classificatory principles.

With this information, we can conclude that the scientific aspect of the bears he is writing about, is the Taxonomy.

Learn more about taxon in brainly.com/question/367202

describing the action potential and its phases

Answers

An action potential is caused by either threshold or suprathreshold stimuli upon a neuron. It consists of four phases; hypopolarization, depolarization, overshoot, and repolarization. An action potential propagates along the cell membrane of an axon until it reaches the terminal button.

Why are certain bacterial infections difficult to treat with antibiotics?

Answers

Answer:

When the Bacteria becomes resistant, the germs spread and grow. In some cases they can they can spread the resistance onto other bacteria's

Explanation:

Select all the statements that specifically give evidence that HIV is a retrovirus.

A. The genetic information is copied from RNA to DNA.
B. The genetic information is inserted into the DNA of the host cell, where it may
remain inactive for many cell cycles and become activated later.
C. The genetic information is transcribed and translated into new viral parts.
D. The parts assemble into new viruses and burst from the host cell.

Answers

Answer:

Explanation:

What is the primary function of dermal tissue?
water storage
protection
nutrient transport
support

Answers

Answer:

Primary dermal tissues, called epidermis, make up the outer layer of all plant organs (e.g., stems, roots, leaves, flowers). They help deter excess water loss and invasion by insects and microorganisms. The vascular tissues are of two kinds: water-transporting xylem and food-transporting phloem.

For a quick simple answer, it's nutrient transport.

Describe what you think about eating or consuming genetically modified foods.
Include a brief explanation of the research points that influenced your opinion.

Answers

Answer:

I think that GMOs don't provide a threat to humans. According to Kurzguzat - In a Nutshell, the "pests" that are engineered into the plant aren't actually harmful to humans. This is called a BT protein and doesn't hurt humans. There were eggplants in Bangladesh that kept getting destroyed by pests, and the genetically modified plant stopped the farmers from using massive amounts of pesticides on the plants.

Explanation:

which fossil record would likely show more diversity in-living organisms of marine organisms?

Answers

Answer:

The correct answer is desert-dwelling species.

Explanation:

Any preserved remains, trace or impression of anything, which was once living in the past is termed as a fossil. The examples of fossils comprise stone imprints of microbes or animals, bones, exoskeletons, shells, coral, remnants of DNA, the substances getting preserved in amber, and others.

For the formation of fossils, the most essential condition is decomposition that takes place gradually, that is, at a slow pace. Thus, places like wet marshy areas will be the locations where the maximum of the fossils can be found as such places provide optimum conditions for slow mineralization and decomposition of bones.

How do the structures of the cardiac muscle and skin tissue support their functions within the body? (Hint: Think abou

Answers

Answer:

See below

Explanation:

The structure of the cell is very much linked with the functions of the cell. The cardiac muscle is made of the myocardium which serves the body by providing the blood, nutrients and oxygen. The cardiac muscles appear striped when seen under a microscope.

The skin consists of the tissues and cells which are close enough to create a boundary that does not allow the entry of materials and pathogens inside the body.

Hence, the function and the morphology of the cells are somewhere related to each other.

The cell walls of bacterial cells and plant cells function inmoving organelles throughout the cell.

modifying lipids and proteins.

producing the cytoskeleton.

maintaining cell shape.

containing DNA.

Answers

Answer:modifying lipids and protiens

Explanation:

Which of the following is similar among all living organisms on Earth?
A.
social behavior
В.
cellular function
C. physical appearance
D.
all of these

Answers

Answer: B

Explanation:

Cellular function is the answer

What controls the ratio of the two isotopes in foraminifera shells?

A. The temperature of the water

B. The salts in the water

C. Water pressure

D. Radiation

Answers

Answer:

A. the temp of the water

Explanation:

a sediment core from the JOIDES Resolution, an ocean-going ship that has collected many sediment cores that record Earth’s past climate.

The ratio of the two isotopes in foraminifera shells is affected by temperature.

What is temperature?

Temperature is the degree of coldness or hotness of an object or a particular place.

Isotopes are atoms of the same element with different masses.

The factors affecting the ratio of isotopes of elements depends on the Half-Life of the isotopes as well as temperature.

Temperature will make the rate of decomposition reaction faster.

The ratio of the two isotopes in foraminifera shells is affected by temperature.

Learn more about isotopes at: https://brainly.com/question/14220416

1. The color of a substance is a
______

Answers

Answer:

pigment

Explanation:

A pigment is a substance occurring either in plant tissue or animal tissue and producing a characteristic colour, such as chlorophyll in green plants and haemoglobin in red blood.

Match the costs to their respective categories.
raw materials
machinery
by-products
employees
odor arising from
production
Internal Costs
External Costs

Answers

Answer:

odor rising from production internal costs

Answer:

internal costs

raw materials

employees

machinery

external costs

odor arising from production

by-products

why is it easy for a virus to mutate?

Answers

Answer:

Viruses mutate very quickly The major reason that viruses evolve faster than say, mosquitoes or snakes or bed bugs, is because they multiply faster than other organisms. And that means every new individual is an opportunity for new mutations as they make a copy of their genetic material. Many of those mutations have no noticeable effect.

Explanation:

What event accompanies energy absorption by chlorophyll (or other pigment molecules) of the photosystems

Answers

Answer:

an electron is exited

Explanation:

as the electrons are released into the system of electron carriers involved with photosystem two, they lose their energy

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