Which of the following is being used as a biofuel in India as an alternative to fossil fuels?

The primary energy source for the Earth is:

$A$ bioenergy source obtained by fermentation to supplement fossil fuel petrol is:

Which of the following is more efficient in converting solar energy?

The rate of biogas production can be limited by

Observe the figures $A$ and $B$ given below and answer the following questions.
$(i)$ The power generation by the above two methods is non-polluting. True/False.
$(ii)$ List any two applications of solar energy.
$(iii)$ What is a photovoltaic cell?