The pigment that is the primary electron donor in photosystem I is: MCQ with Answer and Explanation

Explanation:
Typhoid fever is a bacterial disease caused by Salmonella enterica serotype Typhi. Ringworm is a superficial fungal infection caused by dermatophytes like Microsporum and Trichophyton. Malaria is not caused by a virus; it is caused by a protozoan parasite of the genus Plasmodium. Therefore, statements 1 and 3 are correct, while 2 is false.

Explanation:
Tissue culture is a technique where plant cells, tissues, or organs are grown on a synthetic nutrient medium (like MS medium) under aseptic conditions to regenerate whole plants. It exploits totipotency. It is used for micropropagation, production of disease-free plants, and conservation. Cloning produces genetically identical individuals, genetic engineering alters DNA, hybridization crosses different varieties.

Explanation:
Cyanobacteria (blue-green algae) are photosynthetic, oxygenic prokaryotes that play a crucial role in nitrogen fixation in aquatic and terrestrial ecosystems. Mycorrhiza is a mutualistic symbiotic association between a fungus and the roots of a vascular plant, where the fungus aids in nutrient absorption and the plant provides carbohydrates. Nitrosomonas is a nitrifying bacterium that converts ammonia to nitrite; denitrifying bacteria like Pseudomonas convert nitrates to nitrogen gas. Thus, statements 1 and 2 are correct.