Scientists group organisms based on their common characteristics. which characteristic would be used to construct a cladogram of a particular bird species? a. habitat of the birds b. physical traits of the birds c. types of food consumed by the birds d. methods of reproduction exhibited by the birds

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.