The answer would be “D,” as gravity is the force that keep all objects on Earth’s surface.
It is the nucleus that contains DNA and controls the functions of the cells
Answer: as the predator’s population goes up, the preys will go down, and as the prey’s goes up, the predators will go up. They are basically the opposite of each other.
Explanation: I can’t really tell what your question is. However if there are more prey to eat, then the number of predators will grow because they have more food. However, once there’s too many predators, the number of prey will drop which lowers the amount of food.
Random changes in allele frequency in a population are usually called genetic drift. The reason why this is the answer is because it is a very specific word which is used to describe exactly that - random changes in allele frequency.
All the other cases; answers, here aren't correct and don't apply.
I am not sure what the answer(s) for, "which is not a major function of the kidney?" is but I can guess that your answer for that question might be, regulation of blood cell size. Also, the normal ph range of urine in humans is 6! I hope this helps!