Because the soil didn't have the same nutrients it has now due to lack of decomposition of other plants and animals.
Answer:
O: Type O individuals can donate blood to anyone, because their blood has no antigens. However, they can only receive blood from other type O individuals (because blood with any antigens is seen as foreign).
Answer:
Crossing over occurs in meiosis but not in mitosis
Explanation:
Miosis is a process in which diploid cell becomes a haploid cell.which is essential for sexual reproduction In mitosis the daughter cells are identical whereas in meiosis the daughter cells are different due to crossing over.the process of crossing over does not occur in mitosis.