Consider the following statements:

1.High algal content in water indicates the water is affected by pollution

2.Cyanobacteria are a major indicator of eutrophication in freshwater, as their blooms occur where nutrients are high

ABoth statements 1 and 2 are true ✓ Correct

BOnly statement 1 is true

COnly statement 2 is true

DNeither statement 1 nor statement 2 is true

Correct answer: (A) Both statements 1 and 2 are true

Explanation

Both statements are true: heavy algal growth signals polluted water, and cyanobacteria are a major indicator of eutrophication in freshwater.

Statement 1 is right: abundant algae reflect nutrient-rich, pollution-affected water.

Statement 2 is right: cyanobacteria bloom where nutrient levels are high, flagging eutrophication.

These blooms follow inflows of nitrogen and phosphorus from farms and sewage.

Dense blooms block light and, on decay, drain oxygen from the water.

Some cyanobacteria also release toxins harmful to people and animals.

Want more like this? Create a free account to practise a full test, track your progress, and get spaced-repetition review.