Measure that determines the state of a substance

Why is excretion necessary to maintain homeostasis?

In which situations is the principle of cross-cutting relationship useful in determining relative age?

Follow the directions for self-quiz question 8, draw it, by labeling the appropriate structures with these terms, drawing lines or brackets as needed: chromosome (label as replicated or unreplicated), centromere, kinetochore, sister chromatids, nonsister chromatids, homologous pair, homologs, chiasma, sister chromatid, cohesion