Before thermal energy in fuel can be transferred to the air in heating systems, what has to occur? Its temperature must be raised by converting thermal energy to chemical energy. The energy in its chemical bonds must be converted to thermal energy. The kinetic energy must be stored in the chemical bonds of the fuel. Its temperature must be lowered to transfer energy from the air to the fuel.

The energy in its chemical bonds must be converted to thermal energy

Explanation: when fuel is burnt, the energy used to bind the molecules chemically are liberated as heat.

b brown mice / white sand dunes

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.