Summarize how scientists learn about earth's interior

It is widely accepted that the Earth’s interior is composed of several layers: the crust, the mantle and the core. Since the crust is readily accessible, scientists have been able to perform hands-on experiments to determine its composition; studies on the more distant mantle and core have more limited opportunities samples, so scientists also rely on analyses of seismic waves and gravity, as well as magnetic studies.

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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.