Counting atoms in a compound can be done by taking one element at a time and multiplying the subscript of the element and the number of molecules of the compounds. For example, H2O, there are two atoms of H adn 1 atom of oxygen.
Capillary action is defined as the ability of a liquid to go up a narrow space without the help or opposition of external forces. One of the most important factors affecting capillary action is the intermolecular forces within a substance. The higher the IMF, the greater the capillary action. The H-bonding in water gives it greater IMF than acetone, so water has greater capillary action.
There are many simple ways to prevent erosion. One of the simplest forms of preventing erosion is with vegetation and by establishing root systems that hold the soil together. You can also use geotextiles, fertilizers and also build retainer walls to keep the soil intact and prevent erosion.