How did stars affect life on Earth in the past?

The reason why stars are so important is because they have helped humans navigate through Earth . When it was dark these stars would light up the sky giving people light . ... the most important is the Sun, because without that it wouldn't be life on Earth . Earth would just be a rock with ice.

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.