Which of the following best describes the transfer of fecal coliform and an impact on the environment? Fecal coliform increases the growth of algae in surface water bodies, killing fish.
Digestive problems in humans are elevated from the increase of fecal coliform into drinking water.
Fecal coliform decreases the amount of dissolved oxygen and an overpopulation of fish in surface water bodies occurs.
Fecal coliform increases the amount of organic substances in water and lowers the amount of dissolved oxygen, killing fish.

Fecal coliform increases the amount of organic substances in water and lowers the amount of dissolved oxygen, killing fish.

Explanation:

Fecal coliform are species of bacteria that are found in the intestine of warm-blooded animals like humans etc. Hence, they are released whenever they excrete feaces. Due to this reason, the presence of fecal coliform bacteria in a water body indicates fecal discharge into that water.

The presence of excessive fecal coliform in a water body increases the amount of organic substances in the water. These organic substances are decomposed by bacteria, which causes the oxygen present in the water body (dissolved oxygen) to deplete/decrease. The depletion of oxygen in the water threatens aerobic aquatic organisms e.g fishes and they ultimately suffocate and die.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

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