How do was the carbon cycle most different before 1900s

I would probably say that it was most different because of the cars. The first car was released in 1885, but they weren't really popularized in America until the 1920s. So therefore, Earth's atmosphere was much better than it is now.

the answer is a) a shiprock was formed by igneous process

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.