In a study, a river section near a factory outlet contains only tubifex worms and no stonefly larvae. What does this most likely indicate?

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Question

In a study, a river section near a factory outlet contains only tubifex worms and no stonefly larvae. What does this most likely indicate?

Accepted Answer

C) The water is heavily polluted and has low oxygen levels — Tubifex worms are indicator species that can tolerate heavily polluted, low-oxygen water, while stonefly larvae require clean, well-oxygenated water and are absent from polluted environments. The presence of only tubifex worms strongly indicates the water is polluted with low dissolved oxygen levels.

Answer

C) The water is heavily polluted and has low oxygen levels

Answer

D) The river has too fast a flow rate for stonefly larvae to survive

Answer

B) The water temperature is too cold for most species

Answer

A) The water is very clean and well oxygenated

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