If one species in a community dies out or moves, the community will

The community will slowly decline, or be just fine, or be better off.

Explanation:

Wolves being killed in Yellowstone showed that Yellowstone suffered, because there was nothing to kill the elk, so their population exploded and they ate everything.

If certain rats were gone in certain areas, then the community/environment would be fine, because rats eat birds and other small animals (they eat too many of them).

And if stray cats were gone then certain forests would be better off and see an increase in birds population, stray cats eat birds.

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.