A student investigated the effect of temperature on decomposition by placing identical masses of leaf litter in mesh bags and burying them in soil at three different temperatures (5°C, 15°C, and 25°C). After 4 weeks, the bags were removed and the remaining mass recorded. The results showed that mass loss was greatest at 25°C. Which of the following best explains this result?

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Question

A student investigated the effect of temperature on decomposition by placing identical masses of leaf litter in mesh bags and burying them in soil at three different temperatures (5°C, 15°C, and 25°C). After 4 weeks, the bags were removed and the remaining mass recorded. The results showed that mass loss was greatest at 25°C. Which of the following best explains this result?

Accepted Answer

Higher temperatures increase the rate of enzyme-controlled respiration in decomposers — Award 1 mark for recognising that higher temperatures (up to an optimum) increase enzyme activity in decomposers, leading to faster breakdown of organic matter. A is incorrect — higher temperatures increase enzyme activity up to the optimum. C is incorrect — decomposer activity typically increases with temperature. D is incorrect — the data clearly shows temperature affects decomposition rate.

Answer

Lower temperatures increase the number of decomposer organisms

Answer

Temperature has no effect on decomposition rate

Answer

Higher temperatures increase the rate of enzyme-controlled respiration in decomposers

Answer

Higher temperatures decrease enzyme activity in decomposers

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