Both starch and cellulose are polysaccharides made of individual glucose molecules. Why then can humans digest starch but not cellulose

Starch and cellulose are two very similar polymers. In fact, they are both made from the same monomer, glucose, and have the same glucose-based repeat units. ... Your body contains enzymes that break starch down into glucose to fuel your body. But we humans don't have enzymes that can break down cellulose

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.