In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.
Answer:
Identical twins tend to be more similar to each other than fraternal twins do.
Explanation:
I'm not sure but but i think the answer will be:
A. additive genetic variance times the selection differential.
Answer:
They sleep on just one side of their brain at a time
Explanation:
Dolphins are different from fishes that can breathe underwater.
It is necessary for them to get to the surface of the water at intervals to breathe air.
While sleeping, dolphins allows one hemisphere of their brains fall asleep while the other half is fully conscious. This means that If the left brain is sleeping, the right eye stays open and if the right brain is sleeping, the left eye stays open.
This happens so they always know when it's time to surface and breathe and when to escape when there is trouble.
