13. Scientists have been studying the size of three populations in a river in Ireland. In this ecosystem, pike (a type of big fish) eat perch (a type of small
fish), and perch eat snails. The data showed that all three populations were
stable. Then the snail population increased suddenly. What will likely happen
to the size of the perch population as a result?

answer: 45

explanationyou have to add as well to be it could be

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.