After the occurrence described in Item 14, the phytoplankton concentration . Even though the amount of sunlight continues to increase, the phytoplankton change occurs because of the abrupt reduction in the nutrient concentration. This reduction comes about as phytoplankton, through photosynthesis, combine nutrients with carbon dioxide and water to form organic compounds. The dramatic phytoplankton population growth depletes the nutrient concentration and leads to the inevitable reduction of phytoplankton.

"d.) carbon dioxide and hydrogen sulfide"

helicase, i think thats it

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.

the answer is sex-linked recessive.