(a) List any two

(a) Disadvantages of using fossil fuels are:

(i) Fossil fuels are non-renewable source of energy.

(ii) Elements like carbon, nitrogen and sulphur are present in fossil fuels. When fossil fuels are burnt, these elements react with oxygen of air to produce oxides which are acidic in nature. This leads to acid rain which adversely affects the quality of water and soil.

(iii) CO₂ is a gas which produces green house effeét. This leads to global warming.

(iv) CO produced is a toxic gas that causes respiratory problems.

(b) (i) Examples of renewable sources of energy:

1. Solar energy 2. Tidal energy 3. Hydel power (any two)

(ii) Examples of non-renewable sources of energy:

1. Diesel 2. Petrol 3. CNG (any two)