Muscles convert chemical energy into
a. light energy.
b. nuclear energy.
c. mechanical energy.
d. electromagnetic energy.

Muscles convert chemical energy into MECHANICAL ENERGY.

Body muscles allow humans to consciously move different parts of their body. Muscles depend on the energy obtained from food to carry out their activities of movement. Energy that comes from food is called chemical energy. Mechanical energy on the other hand is the energy that is associated with one motion and position. Thus, in muscles, chemical energy is converted to mechanical energy.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).