The answer is a. natural selection.
<span>In natural selection, genotype variations that will increase
the chance of survival and reproduction of some organism are preserved and will
be inherited. Darwin's theory suggested that there are variations among
individuals in a population and that these variations will help individuals to
survive. According to Darwin, natural selection is the only factor that affects frequency of different variations.</span>
Answer:
bcuz in which habit they have been addicted they can't change it easely after a long try also so it is hard to get people to change their behavior
Answer:
D
Explanation:
Sexual reprduction is when a sperm cell fertilzes an egg cell.
The prenatal circulation of blood is different than the postnatal circulation, mainly because the lungs are not in use. The fetus obtains oxygen and nutrients from the mother through the placenta and the umbilical cord. Blood from the placenta is carried to the fetus by the umbilical vein.
The energy Earth receives off the sun is Solar radiation
