B. Their remote location has kept out invaders.
Answer:
Changes in the pressure create the flow of the air to move up and down in the ear and thus create popping sound.
Explanation:
- The ear-popping is caused by the phenomenon of the opening of the Eustachian tube when one swallows and it might be automatically when you blow our nose or are setting in an airplane and this sound is created when the air enters the middle ear through the tube.
Answer:
The United States gets 81% of its total energy from oil, coal, and natural gas, all of which are fossil fuels. We depend on those fuels to heat our homes, run our vehicles, power industry and manufacturing, and provide us with electricity.
Explanation:
The resource is very plentiful.
