Which of the following sources of pollution decrease the oxygen level of water? select the two correct answers
a) toxic metals
b) radioactive substances
c) plant fertilizer
d) animal manure
e) gasoline

The source of pollution that decreases the oxygen level of water are plant fertilizer and animal manure.

Explanation:

Plant fertilizer that is applied in the agricultural field when enter into the water body, causes water pollution which increases minerals into the water body and animal manure contain raw material which causes eutropication that means increase algal bloom. This indirectly  decreases oxygen availability into the water body.

the overall balanced equation

6co2 + 6h2o > c6h12o6 + 6o2

sunlight energy

where: co2 = carbon dioxide

h2o = water

light energy is required

c6h12o6 = glucose

o2 = oxygen

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.