Answer:
b
Explanation:
It is a fossil of sea shells
Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

Answer:
Hey mate....
Explanation:
This is ur answer....
<em>The number of flights performed globally by the airline industry increased steadily since the early 2000s and reached 38.9 million in 2019. However, due to the coronavirus pandemic, the number of flights dropped to 16.4 million in 2020.</em>
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