<span>there are two types of speciation: allopatric and sympatric. For allopatric speciation there must be a geographical separation between two populations (a mountain for example). For sympatric speciation there are a LOT of possible barriers. Hope this helps! </span>
By the availability of food in plain open. If the main source of food for a certain bird species would be hidden safely in small and hard-to-reach places, then the bird beak would look differently over successive generations, compared to those where food would be easily found on the open.
Genetics
hope this help!! ;)
Blood Capillaries are the smallest of the body's blood vessels they help carry nutrients and oxygen in to the blood stream
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