what did ancient people rely on to explore the world?why are satellites so effective in mapping large areas?what else are scientists are able to tell form scanning besides depth?Sonar gives data like bathymetry which is

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.