Which class of organisms gather their energy directly from the sun?

they are called autotrophs...

Explanation:

Autotrophs,  which also called producers are the organisms which are able to produce the more complex substances like proteins fats and carbohydrates from what is around them (the sun and also carbon dioxide and water...)

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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.