How do atoms, compounds, and molecules affect a living organism

In the practice of science, this type of reasoning is used to develop explanations.

When you aware sick your body produces more leukocytes.briefly describe where the leukocyte are formed,how they are transported,and where they may be stored.

Some steps in cell division are shown below: 1. chromosomes condense and pair up 2. segments of dna of sister chromatids twist and cross 3. exchange of dna occurs between chromosomes 4. four daughter cells are created that are haploid which of the following steps is least likely to occur during meiosis 1?