I. Choose the appropriate word

As/ while/ during energy moves along/ through/ by the ecosystem, much of it is lost at some/ all/ each trophic level. For example, only near/ about/ along 10 percent of the energy stored in grass is incorporated into/ within/ inside the body of a mouse that eats the grass. The remaining 90 percent are/ is/ has stored in compounds that cannot be breaked/ broke/ broken down by the mouse or is lost like/ in the form/ as heat during the mouse's metabolic processes. Energy losses of similar magnitude occur on/ at/ in every level of the food chain; consequently, few/ a few/ little food chains extend behind/ above/ beyond five members (from producer through/ across/ to decomposer), because the energy available at higher trophic levels is to/ too/ two small to support further/ farther/ father consumers.

The flow of energy through the ecosystem drives the movement of nutrients inside/ within/ outside the ecosystem. Nutrients are chemical elements and compounds necessary to living organisms. Like/ not like/ unlike energy, which is continuously lost from the ecosystem, nutrients are cycled through the ecosystem, oscillating among/ between/ through the biotic and abiotic components in what/ which/ that are called biogeochemical cycles. Major biogeochemical cycles contain/ include/ involve the water cycle, carbon cycle, oxygen cycle, nitrogen cycle, phosphorus cycle, sulfur cycle, and calcium cycle. Decomposers play a key role in many of these cycles, returning nutrients to the soil, water, or air, where they can again be using/ useful/ used by the biotic constituents of the ecosystem.

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<== попередня сторінка	\|	наступна сторінка ==>
Vocabulary notes	\|	II. Paraphrase each sentence using the word in bold type

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