Wood burning is a chemical reaction. However, wood does not just spontaneously catch on fire. It needs to begin the chemical reaction.

A) Chemical Energy
B) Physical Energy
C) Electron Energy
D) Activation Energy

a.) chemical energy
explanation: fire needs a chemical reaction which leads to energy in the form of heat being produced. it turns kinetic energy into the form of heat.

A. to determine if humans can explore mars safely

The modern-day generator works on the principle of electromagnetic induction discovered by michael faraday in 1831-32. faraday discovered that the above flow of electric charges could be induced by moving an electrical conductor, such as a wire that contains electric charges, in a magnetic field.