An energy
in their food that has chemical energy inside.
Solar energy converted in to chemical energy by photosynthesis
A chemical reaction need an activation energy to start.
fat
fat
They need a source of energy.A Source of Energy
All chemical reactions need a certain amount of activation energy to get started.
Candle and all Chemical reactions
Chemical energy from the food you've eaten.
Well, if you have electricity, and you want light, then you need to turn electricity into light, which is one kind of energy transformation. If you have chemical energy as in gasoline and wants to go somewhere, you need to turn chemical energy into kinetic energy, and maybe some potential energy as well to get anywhere.
all they need is energy