you are using the energy from food you have eaten(chemical energy), which is being converted into kinetic energy(energy that allows you to move, in this case walk).
source:
year 8 physics class
they walk by using there feet to walk on land
Walk a lot, get a bike.
walk
I went for a walk
Jet-fuel
If you are using bio fuel you are not using fossil fuel. Crude oil is a fossil fuel
they often walk like gorillas by using their hands
air fuel
Airplane pilots "walk on clouds".
Secure the vehicle and walk to the nearest fuel station !
to walk througt wall you need walk througt cheat
I take a walk every morning, It's a long walk from my house to the library.