C is the answer :))))))))))))))))))))))))))))))
<span>Some bacteria in the soil fix nitrogen into useful forms for plants to use them. This conversion of nitrogen helps plants grow. Without the bacteria in the soil a lot of the plants would not be able to grow.</span>
Veins don’t always conduct oxygen poor blood. The pulmonary vein brings reoxygenated blood from the lungs into the heart
In the apple maggot fly, the frequency of certain alleles increases steadily as one goes from North to South. This is an example of: Sympatric speciation.
Sympatric speciation is observed when there are no physical barriers which prevent any members of a species from mating with another, and all members are in close contact to one another. A new species, possibly established on a distinct food source or trait seems to develop instinctively.
The example of apple maggot fly supports a model for sympatric speciation in progress. Hawthorn is the native host for the apple maggot fly in North America. However, in the mid-1800s, a new population developed on introduced, domesticated apple.
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