Answer:
In humans and other mammals, biological sex is determined by a pair of sex chromosomes: XY in males and XX in females. Genes on the X chromosome are said to be X-linked. X-linked genes have distinctive inheritance patterns because they are present in different numbers in females (XX) and males (XY).
Explanation:
When something needs to be transported against its concentration gradient, or a molecule is too big to simply diffuse through a membrane, active transport has to be used. So active transport requires energy (ATP).
Examples:
1. Antiport pumps: transport one substance in one direction while transporting another substance the other way. An example of this is the sodium-potassium pump.
2. Symport pumps - uses a substance that wants to move from an area of high concentration to low concentration and carries another substance against its concentration gradient. An example of this is the sodium-glucose transport protein
3. Endocytosis - large amounts of extra cellular fluid can be taken into a cell - needs ATP to bind proteins in the cell membrane and causes them to change their shape...which eventually causes the surrounding of the fluid to be brought in (a vesicle).
4.exocytosis - opposite of above
<span>The cell membrane acts as the gatekeeper of the cell, determining what goes in and out.</span>
Two diverse species naturally breed an offspring, and selective preserves raver new traits in a given environment, (they evolve).
I hope this helps.=^⊃
The correct answer is A: cell
