The answer to that question is 23, to be exact. Of those 23 countries that divide up the continent, Canada, and the United States comprise nearly 80% of the total land area.
I really hope this reply serves as a complete answer and is exactly what you were looking for.
~Brooke❤️
Freezing and thawing,Plant growth and Abrasion
C. CO<span>2 and other greenhouse gases slowing the escape of heat from earth. </span>
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.