The gland that regulates sleep-wake cycles by secreting melatonin is the: MCQ with Answer and Explanation

Explanation:
Phototropism is the directional growth of a plant in response to light; shoots exhibit positive phototropism (grow towards light), roots negative. Auxin redistribution causes differential growth. Geotropism is gravity response, hydrotropism water, thigmotropism touch. Phototropism optimizes light capture for photosynthesis.

Explanation:
Ascariasis is a helminthic infection caused by the intestinal roundworm Ascaris lumbricoides. Ringworm (dermatophytosis) is a superficial fungal infection of the skin, hair, or nails caused by dermatophytes like Microsporum. Amoebiasis is an intestinal infection caused by the protozoan parasite Entamoeba histolytica, not a bacterium. Thus, statements 1 and 2 are correct.

Explanation:
Helicobacter pylori is a spiral-shaped bacterium that colonizes the stomach lining, disrupting the mucous layer and causing inflammation, leading to gastric and duodenal ulcers. It was discovered by Barry Marshall and Robin Warren (Nobel 2005). S. pneumoniae causes pneumonia, E. coli is gut microbiota but some strains cause diarrhea, B. subtilis is a harmless soil bacterium.