Answer:
All of the above (I, II, III)
Explanation:
Plants (grains) are mostly the organisms found low the food chain, while humans are found at the topmost trophic level on the food chain. Cattle, sheep and goats could be referred to as primary consumers while grains (plants) found at the bottom of the food chain are primary producers. In the food chain, the amount of energy passed from one trophic level to another decreases as only about 10% of energy at a particular trophic level is passed on to the next trophic level.
When humans who are at the topmost trophic level of a food chain feed on primary producers (plants) instead of primary consumers (cattle, sheep), we refer to this as eating lower on the food chain.
When humans eat lower on the food chain (i.e. rely majorly on plants), more grains and agricultural crops would be available for human consumption as a result of less land and grains that would be required to be fed on by primary consumers (cattle, sheep, goats). For example, 1 hectare of grain crop is used to feed cattle, and the cattle is fed on later by humans. If humans feed on grain crops directly instead of feeding on cattle, the 1 hectare of grain crops can serve almost times two of the human population that initially feed on cattle. Less cattle would be kept as humans feed low on grains, which means, more grains would be available as there would be less cattle that would be reared for human consumption. Also, energy lost would be decreased, as more energy gotten directly from the grains would be more than what humans would get when they feed on primary consumers (cattle) that feed on plants
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- Eating lower on the food chain, which refers to humans eating more primary producers than primary consumers (II), would decrease the energy lost from feeding grains to livestock (I), and could increase grain and agricultural crops available for human consumption (III).
