set 2 MCQ Questions & Answers Detailed Explanation

Answer: (b)

Answer: (b)

Crystallization processes of weathering belong to both mechanical and chemical weathering. Mechanical or physical weathering involves the breakdown of rocks and soils through direct contact with atmospheric conditions, such as heat, water, ice and pressure.

Chemical weathering - the process by which the internal structure of a mineral is altered by the addition or removal of elements.

Answer: (b)

Energy flow in an ecosystem is always unidirectional in nature because most of the energy is released at the trophic level in the form of heat and performing metabolic activities.

Hence 10% is transferred from one trophic level to another. This makes a unidirectional flow of energy.

Answer: (d)

The primitive atmosphere of the earth contained : H₂ O, H₂ , NH₃ & CH₄ . The ratio was (2 : 2 : 1) of : NH₃ , CH₄ and hydrogen.

Answer: (d)

Dihybrid condition involves simultaneous inheritance of two pairs of mendelian factors or genes.

Answer: (b)

Organic evolution is the process of cumulative change of living populations and the descendant populations of organisms. According to Darwin, variations are differences among individuals.

Variations which help the individual to fit in its surroundings are passed on to the next generation while others disappear. Thus, variation plays an important role in evolution.