It comes from under the ground. It's black and hard. We use it for heating and making electricity.
coal
It comes from the sun. It's an ecological source of energy.
solar power
A laptop, a fridge and a washing machine need it to work
electricity
It comes from trees. People burn it for heating and cooking.
wood
What do you do to be more ecological?
??
It's where a scientist does his experiments
labolatory
What's the best source of energy in your opinion?
??
It comes from under the ground. It's black and liquid
oil