The Earliest Multicellular Animals in the Fossil Record Are

question 18

Multiple Choice

The earliest multicellular animals in the fossil record are:

• A)jellyfish.
• B)kelp.
• C)trilobites.
• D)worms.
• E)cyanobacteria.

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Definitions:

Limnetic Zone

The open surface waters in a lake, away from the shore, where sunlight penetrates, supporting planktonic and free-swimming aquatic life.

Lakes

Inland bodies of standing freshwater or, in some cases, saline water, usually larger than ponds and contained by land.

Eutrophic

A condition of water bodies, such as lakes and rivers, characterized by an abundant accumulation of nutrients that promote a proliferation of algae.

Mesotrophic

Lakes and water bodies characterized by an intermediate level of productivity, richer than oligotrophic waters but not as nutrient-rich as eutrophic waters.