O2 (oxygen) is a covalent compound
1) Pneumothorax in this case; a spontaneous pneumothorax can be life threatening cause the lung will eventually cause vacuum used by the lung to fill with air, and as you constantly expand your lung it decreases and collapses. So C is going to be the answer.
2) Acetylcholine is the hormone responsible for the "Rest and digest". It is the direct opposite of the Fight and Flight reaction which is marked in Bronchodilation, Increased HR, and increased BP. B
3) Secretin is responsible for stimulating the release of bile by the liver. Secretin is released by the duodenum, the junction of the stomach and small intestines. B
Answer:
B. to understand the world around us
Explanation:
Answer: A scenario often presented to introductory physics classes is that of a "gravity tunnel" — a tube drilled from one side of the Earth to the other through the planet's center. The answer taught for nearly a half-century for how long a fall through such a hole would take was about 42 minutes and 12 seconds.
Explanation: However, solar and lunar gravity, which also perturb orbiting satellites, would eventually pull you into the tunnel wall anyway [source: Darling ]. Strike a chord: Fun fact: A straight line from any point to any other point through the planet would take the same amount of time to fall through like a tunnel through Earth's center.
Answer:
Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period.
