I NEED HELP ON BOTH ANSWER AS QUICKLY AS POSSIBLE!!

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

What is a dendrite and what does it do?

Why do some dna fragments move farther than others during gel electrophoresis? a. because their shapes are different b. because they are different types of molecules c. because the samples are different colors d. because their masses are different