Choose the correct statements from the following.

1.Rivers are flowing water aquatic ecosystems

2.Ponds are still water aquatic ecosystems

3.Streams are still water aquatic ecosystems

4.Deltas are brackish water aquatic ecosystems

A1 & 2 only

B3 & 4 only

C1, 2 & 4 only ✓ Correct

D1, 2 & 3 only

Correct answer: (C) 1, 2 & 4 only

Explanation

Rivers, ponds and deltas are correctly described, giving the true set of Statements 1, 2 and 4.

Statement 1 is right, as rivers are flowing or lotic freshwater ecosystems.

Statement 2 is right, as ponds hold standing or lentic water.

Statement 3 is wrong, since streams are flowing water, not still water.

Statement 4 is right, as deltas mix river and sea water into brackish conditions.

Lotic waters like rivers are generally better oxygenated than still lentic ponds.

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