Consider statements about human blood: 1. Red blood cells lack a nucleus at maturity. 2. Platelets are essential for blood clotting. 3. Plasma constitutes about 45% of blood volume. Which are correct? MCQ with Answer and Explanation

Explanation:
Candidiasis (thrush) is an opportunistic fungal infection caused by Candida albicans, affecting moist areas like mouth, vagina, and skin folds. Ringworm is caused by dermatophytes, athlete's foot by Trichophyton, aspergillosis by Aspergillus.

Explanation:
Nitrogen fixation is the conversion of inert atmospheric N₂ into ammonia (NH₃) by free-living (e.g., Azotobacter) or symbiotic (e.g., Rhizobium) bacteria, or by industrial processes. Nitrification is the oxidation of ammonia to nitrites then nitrates. Denitrification converts nitrates to N₂ gas. Ammonification is the release of ammonia from organic nitrogen by decomposers. Fixed nitrogen is essential for plant growth.

Explanation:
Thyroid-stimulating hormone (TSH) from the anterior pituitary binds to thyroid follicular cells, stimulating the release of T₃ and T₄.