what role do variations have in the theory of evolution by natural selection? i need answer fast pls i will give brainliest to first real answer

Individuals in a population are naturally variable, meaning that they are all different in some ways. This variation means that some individuals have traits better suited to the environment than others. ... Through this process of natural selection, favorable traits are transmitted through generations.

c.more precipitation,but only when emission levels.

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.