Ecology and Environment MCQs for MDCAT

Correct answer: D. Bile Duct

Fasciola hepatica is an endoparasite that lives in the bile duct (and liver) of its definitive host.

Correct answer: A. Aascaris lumberocoides

Ascaris lumbricoides is the common intestinal roundworm parasite shared by both humans and pigs.

Correct answer: C. Chlorofluorocarbon

Chlorofluorocarbons (CFCs) release chlorine atoms in the stratosphere that catalytically break down ozone, depleting the ozone layer.

Correct answer: A. Symbiosis

Mycorrhizae, the mutually beneficial association between fungi and plant roots, is an example of symbiosis.

Correct answer: A. Trophic level

The distinct feeding levels or steps within a food chain, such as producer or primary consumer, are called trophic levels.

Correct answer: A. Ultra-violet radiations

Destruction of the ozone layer allows significantly more ultraviolet radiation to reach the Earth's surface.

Correct answer: B. T2

Herbivores, which feed directly on producers (plants), occupy the second trophic level (T2) of a food chain.

Correct answer: D. Secondary consumer

Organisms at the third trophic level are secondary consumers, which feed on primary consumers (herbivores).

Correct answer: C. Green plants

Most food chains and food webs begin with green plants, the primary producers that capture solar energy through photosynthesis.

Correct answer: C. Littoral zone

The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore.

Correct answer: A. Chlorofluorocarbon

The decline in the thickness of the ozone layer is primarily caused by the increasing level of ozone-depleting substances (ODS), such as chlorofluorocarbons (CFCs), halons, and other similar compounds. These substances are human-made and release chlorine and bromine atoms when they reach the stratosphere. These reactive atoms then catalyze the breakdown of ozone molecules, leading to the depletion of the ozone layer.

Correct answer: A. Forest

Forest buffers act as natural filters and are often the last line of defense, protecting streams and ultimately the Chesapeake Bay from polluted runoff. Forest buffers protect streams and local drinking water supplies by helping to intercept and process excess nutrients, sediments, and pathogens from entering them.