The mass remains the same given that the number of air molecules remain the same and none did escape into the atmosphere.
As heat is being absorbed by the air molecules, they vibrate more vigorously and the electrostatic forces of attraction between the molecules weaken and they become further apart. Hence there is lesser number of air molecules per volume, indicating that density has decreased.
The protists with flagella; move by beating their long whip like structures called flagella. They can have one or more flagella that help them move. Many of these type of protists live in the bodies of other organisms.
On the other hand, protists with cilia; move by beating these tiny hair-like structures (cilia). The cilia act as tiny oars that allows the protist to move through its watery environment. The cilia also help the protists capture food particles. Therefore; both are able to move food particles towards themselves using the respective structures.
Pure substances that have properties entirely different from the atoms that make it up are called compounds. All compounds are made up of molecules, but not all the molecules are compounds. Compounds are composed of more than one mixture of atoms.
