Why was Louis Leakey convinces that Africa was the cradle of humanity

Africa is known as the "Cradle of Humankind" because it is believed that all human life originated in Africa.

Explanation:In 1959, Mary and Louis Leakey were in the Olduvai Gorge in Eastern Africa when they uncovered more than 400 pieces of a fragmented skull. After doing some radiocarbon dating, the Leakey's were able to determine that the skull was 1.75 million years old. This would later become the first evidence that the human species had its roots in Africa.

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.