Daily Olympiad: Biology - Ecology Environment [20260529]

Solution

Correct: B

Carrying capacity is determined by the balance between available resources (abiotic like water, sunlight and biotic like food, competitors) and population demands. Random genetic mutation and predation are secondary factors, while emigration directly affects population size rather than capacity.

Solution

Correct: C

Desert plants like cacti use CAM photosynthesis to minimize water loss and deep taproots to access groundwater. Rainforests have shallow root systems due to high rainfall, savannas have grasses with widespread root systems, and boreal plants are adapted to cold, not arid conditions.

Solution

Correct: B

Nitrification involves two steps: first converting ammonia to nitrite (nitrification step 1) and then to nitrate (step 2). Mineralization releases nitrogen through decomposition, fixation introduces atmospheric nitrogen to soil, and denitrification returns nitrate to atmospheric nitrogen.

Solution

Correct: C

Climax communities represent a stable equilibrium point in ecological succession without further successional changes unless disturbed. Succession does not 'stop' but enters a static phase. Human intervention is unnecessary, and climax communities typically have high biodiversity.

Solution

Correct: C

BOD measures the amount of dissolved oxygen consumed by aerobic microorganisms decomposing organic matter. This is a key indicator of water pollution. Photosynthesis and atmospheric absorption increase oxygen, while nitrification reduces it but not primarily for BOD.