Name a clean gaseous fuel other than LPG and natural gas.

Choose one term from the following which include all others :

coal, natural gas, fossil fuels, petroleum

Why is the process of 'reuse' better than that of 'recycling' ?

Fill in the following blanks with suitable words :

(a) LPG is a ......... fuel but biogas is not a..........fuel.

(b) Glaciers are a source of ...........

(c) One of the main aim of management of forests and wildlife is to conserve the ........... which we hav inherited.

(d) Khadin is a traditional ............ harvesting system in Rajasthan.

(e) When a fuel bums in an insufficient supply of air, then some poisonous gas called ........ is also produced.

What is meant by "sustainable development"?