All cells have A. an internal fluid that gives shape to the cell and supports the other things within it.

B. All of the above

C. either a central zone or a nucleus that contains the cell’s genes.

D. a covering called a plasma membrane that surrounds the cell and controls what information and materials enter and leave it.

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.

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