When fossil fuels are burned, is released into the atmosphere.
a. oxygen
b. nitrogen
c. ammonia
d. carbon dioxide

Carbon dioxide. This is because when fossil fuels are burned, oxygen combines with carbon to form CO2 and with hydrogen to form water (H2O). These reactions release heat that we use for energy. For example, for the same amount of energy produced, burning natural gas produces about half of the amount of CO2 produced by burning coal.

"hydrogen bonding is the attraction of h atoms in the water molecule (slight + charge) to o atoms in a neighboring water molecule (slight - charge); it is a weak interatomic force. but it is still strong enough to the water molecules "stick" together."