set 1 MCQ Questions & Answers Detailed Explanation

Answer: (c)

Answer: (a)

'Origin of Species' book was written by Charles Robert Darwin.

During his world journey (1831–1936) as a naturalist on the H.M.S. Beagle ship, he visited many parts of the world. On the basis of the observations of this journey, he wrote the book thereby describing his theory of natural selection.

Answer: (c)

Down syndrome is a case of Trisomy 21, a genetic disorder caused by the presence of all or part of a third copy of chromosome 21.

Answer: (b)

Answer: (d)

Non-biodegradable substances like pesticide residues cannot be digested or consumed by organisms, so, they are just passed on to organisms of the next trophic level along with food. These non-biodegradable residues keep on accumulating.

The higher the trophic level an organism occupies in the food chain higher will be the accumulation of non-biodegradable pesticide residues.

This phenomenon is called biomagnification. So, the correct answer is 'Biomagnification'

Answer: (d)

A. Producers are the green plants which synthesise their own food using sunlight.

B. Herbivores are primary consumers who feed on producers.

C. Carnivores are secondary consumers who feed primary consumers.

D. Top carnivores are tertiary consumers who feed on other carnivores.

Maximum energy is stored in the trophic levels of producers as they synthesise their own food. They occupy the lowest trophic level and energy is transferred from them to higher subsequent trophic levels. As the energy decreases each time it is transferred to the next higher trophic level, the lowest trophic level i.e. producers, have maximum energy.