I believe all options are correct...
An action potential involves the transfer SODIUM and POTASSIUM ions across an axon's membrane.
During depolarization, when the ion channels open, they allow the influx of sodium ions into the cell, thus changing the electro-chemical gradient of the cell, in order to counter balance this, potassium ions will be allowed to flow out of the cell.<span />
The main food sources of the birds( the plentiful recourses within the environment occupied by the species)
Answer:
B
Explanation:
This involves selectively breeding two or more populations of a species or subspecies with desirable traits that are wanted by the humans. The offspring of the populations will bear the desired traits from the population. Breeding can be done over generations. An example is the breeding a cattle population that is resistant to drought and another that produces more milk. The filial generations will bear both traits.
I believe the answer is delta.
