2. Identify two structures and two activities that are characteristic of cells but not of viruses.

answer; i believe the correct answer to the above question is ( friction)

i think the answer is gold im not entirely sure

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.