Which of the following is a defining characteristic of living organisms that distinguishes them from non-living matter? MCQ with Answer and Explanation

Explanation:
The inner surface of the small intestine is lined with finger-like projections called villi, which increase the surface area for absorption. The epithelial cells (enterocytes) covering these villi have their own microscopic, finger-like projections on their apical surface, called microvilli. Collectively, these microvilli form a 'brush border'. This further massively increases the surface area, maximizing the efficiency of nutrient absorption. Cilia are motile, and stereocilia are found in the inner ear and epididymis.

Explanation:
The Haldane effect describes how the oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin, increasing the removal of CO2. Conversely, deoxygenated blood in the tissues has an increased capacity to carry CO2. This is complementary to the Bohr effect. Exam tip: Bohr = CO2 affects O2; Haldane = O2 affects CO2.

Explanation:
Abiotic components are non-living physical and chemical factors of an ecosystem, including soil, water, temperature, light, and minerals. Biotic components include producers (plants), consumers (animals), and decomposers (bacteria, fungi). The interaction between abiotic and biotic components drives ecosystem functions. Soil provides nutrients and a medium for plant growth.