Fig. 1 shows a compost unit behind a community kitchen. Vegetable peelings and dead plant stems are placed in layers with dry twigs. A volunteer turns the m...
Question 1 Report
Fig. 1 shows a compost unit behind a community kitchen. Vegetable peelings and dead plant stems are placed in layers with dry twigs. A volunteer turns the material each week. Steam is seen leaving the cap on a cold morning, and the inside of the compost is warmer than the air. Bacteria and fungi use the dead material as a source of energy and release mineral ions into the compost.
(a) Identify the group of organisms represented by bacteria and fungi in this system. [1]
(b) Explain why turning the compost can make decomposition faster. [2]
(c) Use Fig. 1 to suggest two reasons why the compost feels warm. [2]
Answer Details
(a) Decomposers [1] (b) Turning adds oxygen [1]; decomposers can respire aerobically / grow and break down material faster [1]. (c) Any two: microorganisms respire [1]; respiration releases energy as heat [1]; insulation from the compost reduces heat loss [1].
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