Consider statements about genetics: 1. DNA replication is semi-conservative. 2. Transcription occurs in the cytoplasm. 3. Translation occurs at ribosomes. Which are correct? MCQ with Answer and Explanation

Explanation:
Alveoli are tiny, thin-walled air sacs surrounded by pulmonary capillaries. Oxygen diffuses across the alveolar and capillary walls into the blood, while CO₂ diffuses out. The trachea, bronchi, and nasal cavity are air passages that do not participate directly in gas exchange.

Explanation:
Elephantiasis, or lymphatic filariasis, is caused by parasitic nematode worms, primarily Wuchereria bancrofti (responsible for about 90% of cases), Wuchereria malayi, and Brugia timori. These worms are transmitted by mosquitoes (like Culex). The adult worms lodge in the lymphatic vessels, causing severe inflammation, blockage, and damage to the lymphatic system. This leads to the accumulation of lymph fluid and massive, disfiguring swelling (edema) of the limbs, genitals, and breasts, resembling an elephant's skin and legs.

Explanation:
Phagocytosis ('cell eating') is the engulfment of large particles or microbes by the cell membrane forming a phagosome. Pinocytosis is 'cell drinking' of liquids. Exocytosis is secretion.