Please help ill give !! when air is heated what happens to its density?

A ) It is increased because the molecules are moving together.
B ) It is increased because the molecules are moving apart.
C ) It is decreased because the molecules are moving together.
D ) It is decreased because the molecules are moving apart

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

Which of the following is the correct definition of chemical energy? a. energy an object has because of its motion or position b. energy resulting from the flow of charged particles, such as electrons or ions c. energy produced from the splitting of atoms d. energy stored in chemical bonds of molecules

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.