Propulsion of a sperm cells occurs due to and It gets energy from/_

propulsion of a sperm cells occurs due to the sperm's tail containing a large number of proton channels called Hv1 and It gets energy from the seminal plasma.

Explanation:

mammal

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.