What role does the spark from the igniter play in the reaction that takes place when propane is burned in a gas grill?

a
the spark provides enough energy to break the bonds of the product molecules and get the reaction started.
b
the spark provides enough energy to stop the reaction.
c
the spark provides enough energy to break the bonds of the reacting molecules and get the reaction started.
d
the spark cools down the reaction.

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.