Why does dna replication have to occur before every cell division?

Which of the following systems in absorbing oxygen and releases carbon dioxide

How is mitosis different in plants and animals? a. in animals, the cell membrane pinches together. b. in plants, the dna is one circular chromosomes. c. in plants, there are no sister chromatids. d. in animals, a new cell wall forms.

Agenus is a taxonomic grouping that identifies a collection of species. when a scientist discovers a new species, how is this species assigned to a genus