Help! this is due today!! 1) Why do muscle cells have so many mitochondria?

A: The mitochondria in muscle cells are smaller so more are needed.
B: Muscle cells are bigger than every other cell and can fit more mitochondria.
C: There are more mitochondria only because there are more nuclei.
D: Muscle cells need to quickly respond to energy needs.

2) What is the effect when a muscle contracts? *

A: The muscle pushes on another muscle.

B: The muscle pushes on a bone.

C: The muscle lengthens.

D: The muscle shortens.

4) Which of the following is stored in the skeletal system?

A: potassium

B: calcium

C: sodium

D: water