Question

River and lake are filled with water hyacinth what is meant by migration describe the life cycle of birds give two causes of air pollutions

Answer 1

Answer:

from cars , train , rockets

from factories

Answer 2

Water in rivers and lakes is being reduced as the requirements of rapid urbanisation, population growth and industrialisation cause more water to be drained out from them. The main causes of river pollution are :

(i) Huge amounts of untreated sewage and industrial effluents are being empried into the rivers and lakes. This has caused the water bodies to become highly polluted

(i) Human ashes (due to cremation near water bodies), dead animals and leaching out of nitrogen compounds from fertilised agricultural lands also increase the pollution

(ii) Nutrient run-off in storm water from sheer flow' over an agricultural field or a forest is also another cause.