Consider two mammalian cells, one in G1 and the other in G0 (stationary) phase. If they are stimulated to pass the restriction point by the addition of an extracellular proliferation signal, but the signal is then immediately removed, what would you expect to happen?A, Both cells will replicate their DNA. B. Only the G1 cell will replicate its DNA. C. Only the G0 cell will replicate its DNA. D. Only the G1 cell will start to replicate its DNA, but will stop halfway through the replication and will not reach G2.E. Neither of the cells will replicate their DNA.

A, Both cells will replicate their DNA.

Explanation:

During the cell division, cell passes through several phases and divides. Before each phase, the cell has to pass through the checkpoints. At these cell checkpoints, the cell receives the internal and external signals.

When the cell is arrested at G₀ phase, the cell does not divide until it receives a signal to proliferate but when the cell passes the G₁ phase, the cell will divide continuously.

In the given question, if the cells when in their G₀ and G₁ phase receive proliferation signal, the G₀ phase cell will also divide and will replicate it DNA during S phase as G₁ phase cell will do.

Thus, Both the cells will divide their genetic material.

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.