The theory of 'use and disuse' was proposed by: MCQ with Answer and Explanation

Explanation:
Variant CJD is a fatal prion disease linked to consumption of beef from cattle with bovine spongiform encephalopathy (mad cow disease). Prions are misfolded proteins that induce other proteins to misfold. Not viral, bacterial, or fungal.

Explanation:
The cohesion-tension theory (transpiration pull) is the primary mechanism for water ascent in tall trees. Transpiration creates negative pressure (tension) in leaves, water molecules cohere, and the column is pulled up. Root pressure and capillary action play minor roles. The cohesion of water is due to hydrogen bonds.

Explanation:
Consciousness is the defining property of living organisms, allowing them to sense and respond to stimuli. Non-living objects can increase in mass (e.g., crystal growth), crystallize, or exhibit magnetism, but they lack consciousness. Reproduction and metabolism are also key characteristics, but consciousness is the most fundamental feature. Thus, only living things possess this ability.