<span>The tone, before conditioned to salivation, is simply a stimuli that the dog is responding to or ignoring in it's environment. Since it has no taught reactions to this sound, it is simply part of the environment the dog is in.</span>
A Eukaryotic cell contains a nucleus; more than one chromosome and is typically a multi-celled organism. Both plant and animal cells are eukaryotic cells. A Prokaryotic cell does not contain a nucleus. It only contains one
chromosome and is a single-celled organism. It was the only form of life
on earth for millions of years. Examples of a Prokaryotic cell are the
different types of bacteria present today.
The natural selection is the survival of the fittest, which means that o<span>nly the best adapted individuals survive and reproduce, contributing the most to the next generation</span>
According to natural selection, birds such as cardinals , eagles, and ducks have differently shaped feet due to <span>adaptation to different environments and feeding habits.
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