the lactose operon in E. coli is an example of a gene that is expressed when lactose is not available in a cell, what does it mean

What best explains the inability for life to exist in earth early atmosphere

Explain how scientists use geologic time to determine the age of landforms.

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