Answer: 3
Explanation: I took the k12 quiz
As the air molecules move through the valve they have friction as they hit the walls, and its this friction that causes it to heat up.
Answer:
Carbon has the ability to form very long chains of interconnecting C-C bonds. This property allows carbon to form the backbone of organic compounds, carbon-containing compounds, which are the basis of all known organic life. Nearly 10 million carbon-containing organic compounds are known.
