Which of the following is NOT true of the muscular system?
A. They are connected to bones.
B. They allow voluntary movement.
C. They allow us to move.
D. They are connected by gap junctions.

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

i think its white blood cells

i hope this