Read the following statement. I. In a food chain, there is a multidirectional flow of energy from the sun to producers, consumer and decomposer. II. Shorter food chains provide more energy as compared to longer food chains. III. In an ecosystem, no food chain is independent. IV. If 100 joules of energy is available at the producer level, then the amount of energy present at the level of the secondary consumer is 10 joules. Which of these statements are correct? A. I and II B. II and III C. III and IV D. I and IV Answer Class 10 Science

Which of these statements are correct?

1. I. In a food chain, there is a multidirectional flow of energy from the sun to producers, consumer and decomposer.
2. II. Shorter food chains provide more energy as compared to longer food chains.
3. III. In an ecosystem, no food chain is independent.
4. IV. If 100 joules of energy is available at the producer level, then the amount of energy present at the level of the secondary consumer is 10 joules.

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Answer

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Hint:

Food chain is defined as the series or sequence of flow of energy in terms of food from the producers to the decomposers. It describes the succession of eating and being eaten by other organisms.

Complete Answer:

• In a food chain, the flow of energy takes places from producers to decomposers. The producers (plants) produce food by utilising the sunlight.
• The plants are eaten up by the primary consumers or the herbivores which are further eaten by the carnivores or the secondary consumers. The flow of energy is unidirectional. (❌ Statement I is incorrect)
• In a food chain, only 10% of energy is transferred from one trophic level to another.
• The shorter the food chain, the more energy is available. (✅ Statement II is correct)
• Food chains are not independent; they interconnect to form food webs. (✅ Statement III is correct)
• If 100 joules of energy is at producer level, only 10 joules reach primary consumers, and 1 joule reaches secondary consumers. (❌ Statement IV is incorrect)

Thus, the correct option is: (B) II and III

Note:

A food web is an interconnected system of food chains showing how organisms rely on each other for food. Food chain = linear; Food web = complex graph.