Polluted water bodies have usually very high abundance of plants like Nostoc and Oscillitoria. Give reasons.

Polluted water bodies possess high algal growth due to the presence of nutrients. These nutrients increase the rapid growth of water plants, i.e., algae especially Nostoc and Oscillitoria, etc., and result in colonies. These colonies are generally surrounded by a gelatinous sheath and further leads to the formation of blooms in water bodies.