Name the functions of the four components of the digestive system: G1 Tract

Motility: Mechanical breakdown and mixing of ingested nutrients by smooth muscle movements, passage of nutrients through the digestive tract, and elimination of undigested or unabsorbed residues from the body.

Secretion: Release of enzymes, hormones, and other substances that take part in digestion.

Digestion: Chemical reduction of ingested nutrients into particles, then into molecules small enough to cross the lining of the gut and reach the internal environment of the body.

Absorption: Passage of digested nutrients from the gut lumen into the blood or lymph, which distributes them throughout the body.

Explanation:

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.