Answer:
B. a food chain
Explanation:
Food chain: a hierarchical series of organisms each dependent on the next as a source of food.
Boys need 2,400 to 3,200 a day, while girls need 1,800 to 2,400 a day.
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Answer:
B. After clearcutting, plant uptake stopped and nitrogen accumulated in the soil.
Explanation: Clear cutting leaves the soil bare and allows for direct penetration of sunlight this increases the soil temperature which favors the activity of soil microrganism. This microrganism activity increase the production of ammonium and nitrate hence the increase in soil Nitrogen level. Clearcutting then allows for accumulation of Nitrogen produce due to removal of plant or forest tree that could use up the Nitrogen produced.
