Answer:
b. x chromosome inactivation
Explanation:
As you know, female cats have an x chromosome inherited from their mother and an x chromosome inherited from their father. After these two chromosomes are inherited and determine the sex of the cat, one of them will be disabled at some point in fetal development. Inside the X chromosome is the gene that determines the coat color of cats, when one of the two x chromosomes is deactivated, the other x chromosome will have all of its cells activated. In this case, if the activated chromosome is the one that has genes for the "cheetah" pattern of the coat color, all the descendants of this female cat also have the same coat.
The cell membrane is said to be selectively permeable is because it allows a select few things to go through while stopping the passage of other stuff.
I think its D. but I'm not sure
The reason being is it's a prosses that doesn't require the "help" or "cooperation" of other cells and it only effects the one cell.