Fill in the blanks spaces using the answers provided. carbon ii Oxide, ventilated, crude oil, animal waste, insulated, sun.

1. Solar energy is derived from the .
2. Houses should be to prevent loss of heat.
3. Biogas production depends mainly on availability of .
4. Paraffin and gas are products of .
5. Charcoal should be used in a well room.
6. is a poisonous gas produced when charcoal burns.