How successful has it been in reducing the harmful chemicals from the burning of fossil fuels that cause acid rain?

Not very successful considering the fact that there is still acid rain even with more advances in technology such as the development of hydroelectric power plants and other renewable forms of energy so as to reduce the continuous burning of fossil fuels.

Explanation:

Acid rain is produced when sulfur and nitrogen in their oxide forms are released into the atmosphere where they get to meet with water and other chemicals. Since water contains hydrogen and oxygen, it reacts with sulfur and nitrogen in their oxide form to produce weak acids which come down to the earth as it rains. Fossil fuel combustion is a man-made practice of releasing sulfur and nitrogen in their oxide form into the atmosphere which eventually results in acid rain.

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.