The wind chill index tells you
a. the temperature of the water during winter
b. the amount of moisture in the air
c. how wind speed affects heating needs for structures
d. how wind and temperature affect your body in winter

The correct answer is D.how wind and temperature affect your body in winter. Basically, it's how you perceive the cold weather on your skin regardless of what the temperature actually is. It's usually lower and that's why you have forecasts say that it will be for example 0, but it will feel like -5 degrees Celsius.

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.