Answer:
The populations become adapted to different environments and eventually become so different that they cannot interbreed to produce fertile offspring.
Speciation is the evolution of one species into two different kinds, and when they become isolated, that is the final step, since they cannot interbreed any longer.
Answer:
Your answer is photosynthesis.
Well the food that heterotrophs eat are either the autotrophs who photosynthesize, or other heterotrophs. When they eat the autotrophs the energy stored in the plant matter gets transferred to them. If another animal was to eat the initial consumer of the autotrophs then they would be getting the energy stored in that animal that was obtained by eating the autotrophs who had the initial energy.<span>
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Unicellular eukaryotes<span> are </span>single-celled<span> organisms, all of which were traditionally classified in the kingdom Protista. The term "</span>unicellular" denotes that these organisms have only one cell, while the term "eukaryote<span>" means that each of these cells has a nucleus -- and other organelles -- held in place by membranes.</span>
