Which of the following was a major milestone that allowed for greater diversity of life during the paleozoic era?
1.many marine animals became extinct.
2.photosynthetic prokaryotes produced more oxygen.
3.animals moved from the sea to the land.
4.reptiles became more diverse.

the correct answer is b. possesses the characteristic of compartmentalization of organelles, wherein the organelles are bound by membranes.

explanation:

it would lead to upper respiratory infections and pneumonia.

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.