This is mendel's first law. for each inherited trait, there are at least one pair of alleles. this states that during gamete formation each member of an allelic pair separates from the other member to form the genetic make-up of a gamete (sex cell).

law of segregation is the answer

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.

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.