A f---------- fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms

A--------- rain is one of the consequences of air pollution. It occurs when emissions from factories, cars or heating boilers contact with the water in the atmosphere.

P--------------- is the introduction of contaminants into the natural environment that cause adverse change.

Using cloth bags instead of plastic ones is environmentally- f----------

S--------------- energy is energy that we will never use up or deplete. It is inexhaustible, like , for example, the kind we get from wind, sun or water.

A carbon f-------------- is the total amount of greenhouse gases (including carbon dioxide and methane) that are generated by our actions.

A h-------------- car is one that uses more than one means of propulsion - that means combining a petrol or diesel engine with an electric motor.

Don´t leave the water r--------------- when you´re doing the dishes.

Cutting down trees without restrictions brings about d-------------------

It´s vital to use r--------------- energies like the solar one because they pollute less than the traditional sources of energy.

The main effect of the melting of the Poles is the sea level r----------

S------------ is air pollution that reduces visibility. It is a mixture of "smoke" and "fog".

C----------- ch------------ is the most evident effect of global warming: temperatures aare becoming more extreme all over the world.