Which of the following matches a human action with its impact? a) construction of dam: scarcity of water for animals b) use of fertilizers: increase in the population of aquatic animals c) decrease in honeybee population: increase in plant population d) construction of roads: improvement in quality of water in local lakes

Hi!

The correct option would be A) construction of dam: scarcity of water for animals

Option A is correct because most animals are dependent on free-flowing rivers and freshwater for their water supply. During the building of a dam, rivers are redirected from the regions they previously supplied to the dam, which deprives the animals of what was their source of water. Dams also cause reduced quantity and flow of water in rivers, leading to scarcity of water for animals that relied on it as a source.

Option B is incorrect because fertilizers reduce the population of aquatic animals. When fertilizers wash out from the soil and drain into water bodies, they increase the contribute to the increase of nutrients and chemicals which prove to be harmful to aquatic life. These nutrients, which include mainly nitrogen, help various plant lifeforms and algae to grow. This results in a drastic overgrowth in algae populations, and algae in turn produce chemicals that are toxic to aquatic animals. The overgrowth of plants and algae also demand a higher oxygen concentration, and this may result in an oxygen deficiency of it in, suffocating other aquatic animals.

Option C is incorrect because honeybees play an essential role in pollinating various plants, serving to increase their population.

Option D is incorrect because the construction of road often involves chemical spillages and production of harmful pollutants, exhaust fumes, tire and pavement wear, which if not taken care off, run off into nearby local lakes thereby having a bad impact on water quality.

Hope this helps!