The Function of a Kidney Is Similar to Which Part

Multiple Choice

The function of a kidney is similar to which part of the diagram below?

A) It is similar to the water because the body is primarily composed of water.
B) It is similar to molecule A because the kidney contains a lot of urea.
C) It is similar to molecule B because the kidney contains a lot of glycogen.
D) It is similar to the container, because the kidney's function is to hold urine.
E) It is similar to the semipermeable membrane because the kidney's function is to remove waste products but retain proteins.