Answer: Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.
Explanation:
Answer:
C. The evolution of many species from a single ancestor over a long period of time
The circulatory system - hemoglobin in the blood transports oxygen :)
The answer is B . two atoms exchange electrons and become ions
