Question

1. What's the solution?
Rivers and lakes are filled with water hyacinth.​

Answer 1

Explanation:

$During \: the \: daytime,  \: water \: hyacinth  \: release \: oxygen \: but \: at \: night \: time \: they \: too \: require \: oxygen. \: This \: causes \: depletion \: of \: dissolved \: oxygen \: in \: the  \: water \:  and \: hence \: many \: other \: organisms \: die \: due \: to \: lack \: of \: oxygen. \: ... Such \: a  \: water \:  body \: gets  \: filled \: with \: water \: hyacinth.$

Answer 2

Answer:

During the daytime, water hyacinth release oxygen but at night time they too require oxygen. This causes depletion of dissolved oxygen in the water and hence many other organisms die due to lack of oxygen. ... Such a water body gets filled with water hyacinth.

Explanation:

$hope \: it \: helps$