which of the following must occur before cell division? check all that apply.

1. the cell creates proteins.

2. the amount of dna increases.

3. damaged cells are removed.

4. the cell increases in size.

The rate at which molecules water and oxygen can enter a cell is determined by the-

Ras is a g-protein that is activated when a growth factor attaches to egfr. its activation results in the replacement of a gdp molecule with a gtp molecule, thus allowing a signal transduction pathway to be activated. considering the signal pathway illustrated on this page, what is one potential outcome of a mutation in the ras gene that leads to ras protein hyperactivity. be specific.

Up to what percentage of the world's flora consisted of cycads during the triassic period? 100% 75% 50% 20%