Name the process responsible for large energy production in the sun?

Mention any four areas where solar cells are being used as a source of energy.

Describe the steps involved in obtaining biogas and explain what is meant by anaerobic decomposition.

What is a solar panel?

How is the slurry left over after the generation of biogas in a biogas plant used?

Why is the use of biomass to generate heat:
$(i)$ discouraged by burning it directly in ovens (chulhas),and
$(ii)$ encouraged for obtaining biogas through a biogas plant?