The current consumption of domestic firewood in India is about:

Which of the following is an incorrectly matched pair?

The calorific value of biogas is

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?

The sap of which plant is considered a good substitute for diesel oil?

Major autotrophic biomass in oceans is contributed by