Environmental Science MCQs

743. The occurrence of pesticides like DDT in higher trophic levels is termed as

A. bioremediation
B. biomagnification
C. biological enhancement
D. biopollution
✅ The correct answer is option B.
Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain.

744. _________ is a mixture of 50 – 90% of methane

A. Natural gas
B. Air
C. Water
D. Bio diesel
✅ The correct answer is option A.
Methane also is the chief constituent of natural gas, which contains from 50 to 90 percent methane (depending on the source), and occurs as a component of firedamp (flammable gas) along coal seams.

747. Boron, Zinc and Manganese are usually referred to as

A. Micronutrients
B. Macronutrients
C. Soil Vitamins
D. MBZ nutrients
✅ The correct answer is option A.
Zinc, Chlorine, Boron, Molybdenum, Copper, Iron, Manganese, Cobalt and Nickel are called micro-nutrients. They are called so because they are found and needed by plants in very small amount relative to other nutrients and are least likely to be limiting plant growth and healthy development.

749. A biomass pyramid is important because it illustrates

A. How energy flows through a food web
B. The number of species in each tropic level
C. The biomass of all organisms at each tropic level in a system
D. The number of tropic levels in a system
✅ The correct answer is option D.
Biomass pyramids show how much biomass (the amount of living or organic matter present in an organism) is present in the organisms at each trophic level, while productivity pyramids show the procreation or turnover in biomass.