Consider statements about ecology: 1. Producers form the base of the food chain. 2. Decomposers recycle nutrients back into the ecosystem. 3. Energy flows bidirectionally in a food chain. Which are correct? MCQ with Answer and Explanation

Consider statements about ecology: 1. Producers form the base of the food chain. 2. Decomposers recycle nutrients back into the ecosystem. 3. Energy flows bidirectionally in a food chain. Which are correct?
A. 1, 2 and 3
B. 1 and 3 only
C. 1 and 2 only
D. 2 and 3 only
Answer: Option C
Solution (By JKExamLibrary)
Producers (autotrophs like green plants) form the first trophic level and the base of all food chains, converting solar energy into chemical energy. Decomposers (bacteria and fungi) break down dead organic matter and waste, releasing essential inorganic nutrients back into the soil for producers to use, thus completing the nutrient cycle. Energy flow in an ecosystem is strictly unidirectional, moving from the sun to producers and then to consumers, and is eventually lost as heat; it does not flow bidirectionally. Thus, statements 1 and 2 are correct.

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Practice More Biology Questions

Question #1
Which of the following is a correct statement about the human skeleton?
A. The vertebral column is composed of 33 bones in adults.
B. The femur is the smallest bone in the body.
C. The skull consists of 22 bones, all fused into a single unit.
D. The rib cage has 10 pairs of ribs.

Correct Answer: Option A


Explanation:
The adult vertebral column consists of 33 vertebrae (though some are fused: 5 sacral and 4 coccygeal). The femur (thigh bone) is the longest and strongest bone. The skull is composed of 22 bones (cranium and facial bones), some fused but the mandible is movable. The rib cage has 12 pairs of ribs. The stapes in the ear is the smallest bone.

This question belongs to: Science Biology
Question #2
The type of immunity resulting from the injection of ready-made antibodies is:
A. Cell-mediated immunity
B. Innate immunity
C. Active immunity
D. Passive immunity

Correct Answer: Option D


Explanation:
Passive immunity is acquired by receiving pre-formed antibodies from another source, providing immediate but temporary protection. Examples: antivenom, immune globulin injections, and maternal antibodies. Active immunity is generated by the body's own immune system (infection or vaccination). Innate is non-specific, cell-mediated is T-cell based.

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Question #3
Which of the following is a water-soluble vitamin that acts as a coenzyme in energy metabolism?
A. Vitamin D
B. Vitamin A
C. Vitamin B₁
D. Vitamin E

Correct Answer: Option C


Explanation:
Vitamin B₁ (thiamine) is water-soluble and functions as a coenzyme (thiamine pyrophosphate) in carbohydrate metabolism, particularly in decarboxylation reactions. Vitamins A, D, E, and K are fat-soluble. B₁ deficiency causes beriberi and Wernicke-Korsakoff syndrome. Being water-soluble, excess is excreted in urine and toxicity is rare.

This question belongs to: Science Biology