Bacillus thuringiensis (Bt) is widely used as a: MCQ with Answer and Explanation

Explanation:
Sulfur is present in the amino acids methionine and cysteine (which forms disulfide bonds in proteins). Nitrogen is in all amino acids, phosphorus in nucleic acids and ATP, iron in heme. Sulfur is also in vitamins biotin and thiamine. Disulfide bonds are crucial for protein tertiary structure.

Explanation:
Kala-azar, also known as visceral leishmaniasis, is caused by the protozoan parasite Leishmania donovani. It is transmitted by the bite of the infected female sandfly (Phlebotomus). The disease affects internal organs, particularly the liver, spleen, and bone marrow, causing prolonged fever, weight loss, and enlargement of the liver and spleen. Trypanosoma brucei causes sleeping sickness, and Plasmodium causes malaria.

Explanation:
The liver contains enzymes (cytochrome P450 system) that metabolize and detoxify alcohol, drugs, and other xenobiotics, converting them to less toxic, excretable forms. The kidneys excrete waste, stomach digests, pancreas secretes enzymes.