We cannot consider something to be work unless
a. force is applied to an object resulting in balanced forces
b. forces that caused the action were unbalanced and the action occurred in the opposite direction
c. action was equal to the reaction and was the result of a balanced force
d. force applied causes movement of an object in the same direction as the applied force

answer:

a

explanation:

i just know

lipid

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.