Sources of heat from inside earth is radioactive decay and residual heat.
Species could compete for water, food, land, etc.
Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.
The correct answer would be the second option. The type of electromagnetic radiation that is used in kitchen appliances and in radar guns would be microwaves. They have wavelengths from 1 m to 1 mm. It is used in heating and cooking in some kitchen appliances and are being used in radar guns to send signals.
