Which of the following is true about a theory? O A. It will be modified or replaced.
O B. It is the first step toward scientific knowledge.
O C. It is a guess about how something in nature happens.
D. It is almost always controversial among scientists.

a) electrical > light, sound, and thermal< < < <

) the mechanical energy of the firefighter moving.< < < < a) electrical > light, sound, and thermal< < < <

c) both a and b.

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide