What is the difference between a cell wall and a cell membrane a. cell walls do not connect cell to cell. cell membranes connect cell to cell. b. cell walls contain vesicles. cell membranes contain plasmids. c. only plant cells have cell walls. only animal cells have membranes. d. the cell walls has a rigid structure. the cell membrane is flexible.

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.