Which of the following is not a way carbon dioxide returns to the atmosphere

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

How did planetesmals form planets? a. they broke apart into smaller chunks.b. they collided and stuck together.c. they cooled and pulled ice together.d. they began to rotate.

Asolution contains 225 g of sodium chloride, nacl, dissolved in enough water to make a 0.25 l of solution. what is the molarity of the solution?