Which of the following represents secondary succession? a
Plants growing in a forest that was destroyed by fire.
b
Plants growing on sand dunes.
c
Plants growing on a new volcanic island that formed in the ocean.
d
Moss growing on top of rocks.

i think the answer is A: plants growing in a forest that was destroyed by fire.

Explanation:

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.