That statement is true because to make a diluted solution, you have to add more solvent than the solute in a concentrated solution. This is extra information, but to make a diluted solution more concentrated, you have to add more solute since a concentrated solution has an excess amount of solute as stated before.
A cloud that forms on the ground is called fog. Some clouds you see in the sky might be from airplanes. These are called contrails. High level cirrus clouds may travel at speeds up to 100 mph.
