Consider statements about cell biology: 1. The Golgi apparatus packages materials for secretion. 2. The smooth ER is involved in lipid synthesis. 3. The rough ER is involved in lipid synthesis. Which are correct? MCQ with Answer and Explanation

Explanation:
Earthworm (Pheretima) belongs to phylum Annelida, characterized by metameric segmentation (body divided into segments), a closed circulatory system, and setae for locomotion. Tapeworm is a platyhelminth (flatworm), roundworm is nematode (Ascaris), Planaria is a free-living platyhelminth. Annelids include polychaetes (Nereis), oligochaetes (earthworm), and hirudinea (leech).

Explanation:
The Widal test is a serological agglutination test used to diagnose enteric (typhoid) fever, caused by Salmonella enterica serotype Typhi. It detects the presence of specific antibodies (O and H antigens) in the patient's serum against the O (somatic) and H (flagellar) antigens of the Salmonella typhi bacteria. A significant rise in antibody titer indicates an active or recent infection. It is not used for TB (Mantoux test), malaria (blood smear), or dengue (NS1/IgM).

Explanation:
The kidneys regulate blood pressure via the renin-angiotensin-aldosterone system and by controlling fluid volume. The nephron's glomerulus filters blood plasma into Bowman's capsule. Humans are ureotelic, meaning the primary nitrogenous waste excreted is urea, not ammonia (which is highly toxic and excreted by aquatic animals). Thus, statements 1 and 3 are correct.