Another important aspect of meiosis and the sexual life cycle is the role these processes play in contributing to genetic variation. Although offspring often resemble their parents, they are genetically different from both of their parents and from one another. The degree of variation may be tremendous.
The following processes are associated with meiosis and the sexual life cycle:

a. DNA replication before meiosis
b. crossing over
c. chromosome alignment in metaphase I and separation in anaphase I
d. chromosome alignment in metaphase II and separation in anaphase II
e. fertilization

a, b, c and e are correct

The point d is incorrect because the chromatids of each chromosome are aligned in metaphase II and then they are separated in anaphase II

Explanation:

The DNA replication occurs during interphase  

The crossing over, also known as recombination, produces genetic variation during cell division

The chromosomes are aligned in metaphase I and then they are separated in anaphase I

answer: after carbon dioxide enters the leaf through stomata it moves into the mesophyll cells where photosynthesis occurs and glucose is constructed. respiration occurs when glucose (sugar produced during photosynthesis) combines with oxygen to produce useable cellular energy.

explanation: