Cosmic microwave background radiation is the term used for the microwave
radiation observed everywhere in the universe. The existence of this radiation is
used as evidence to support the Big Bang Theory because, in our current
understanding, this radiation is -
energy left over from the rapid expansion of matter.
the result of high speed collisions of atoms.
an indication that the universe is getting hotter.
proof that the size of the universe is decreasing,

well for one plants are always the producer, so a is the answer. a wolf is more of the consumer(predator) and the deer is the prey so i know those two are out of the question. also mushrooms are fungi/fungus so a is the producer.

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.

what in the weirdo : o