The action by which a plant grows toward sunlight is called

response to stimulus

using energy

reproduction

movement

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

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.

the glands which are associated with each description is given below: