Overfishing of upper-trophic-level fish has led to humans seeking new species to harvest at lower trophic levels. this is called:

fishing down the food chain

explanation:

it's anything that aren't producers and consumers.

explanation:

you've got to be clear on what "this" is

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.