The answer is the G1 checkpoint
Answer:
There are 3
Explanation:
Parenchymal, Collenchymal, and Sclerenchymal.
<span>Intrinsic factor is a glycoprotein principally secreted by the parietal cells of the stomach. This secretion is needed to produce mature erythrocytes. Its secretion is governed by the same biochemical processes that regulate acid secretion and its action is to assist in the absorption of vitamin B12.</span>