Consider statements about human diseases: 1. Common cold is caused by a virus. 2. Typhoid is transmitted through contaminated food and water. 3. Plague is transmitted by the bite of a rat flea. Which are correct? MCQ with Answer and Explanation
Consider statements about human diseases: 1. Common cold is caused by a virus. 2. Typhoid is transmitted through contaminated food and water. 3. Plague is transmitted by the bite of a rat flea. Which are correct?
A. 2 and 3 only
B. 1 and 3 only
C. 1 and 2 only
D. 1, 2 and 3
Answer: Option D
Solution (By JKExamLibrary)
The common cold is a viral infection of the upper respiratory tract, primarily caused by rhinoviruses. Typhoid fever, caused by Salmonella typhi, is transmitted via the fecal-oral route through contaminated food and water. Plague, caused by Yersinia pestis, is a zoonotic disease transmitted to humans primarily by the bite of infected rat fleas (Xenopsylla cheopis). All three statements are correct.
Explanation:
Phloem transports organic solutes (mainly sucrose) from source to sink. Xylem transports water and minerals. Phloem is composed of sieve tubes and companion cells.
Explanation:
Blood group O lacks A and B antigens on red cells but contains both anti-A and anti-B antibodies in plasma. This makes it the universal donor for packed red cells but dangerous plasma donor. Group AB has no antibodies. So, the presence of both antibodies is correct.
Explanation:
Vitamin E (tocopherol) is a lipid-soluble antioxidant that scavenges free radicals and prevents lipid peroxidation of cell membranes. Vitamin C is water-soluble antioxidant, A is for vision, K for clotting.
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