Solution. 1  This species has a 2â charge on it, so it is an anion. Anions are named using the stem of the element name with the suffix -ide added. 2  Because this species has no charge, it is an atom in its elemental form. This is cobalt. 3  In this case, there is a 2+ charge on the atom, so it is a cation.
1. 2. 3. The walls of the alveoli are composed of a single layer of flattened epithelial cells, as are the walls of the capillaries, so gases need to diffuse through just two thin cells. The alveoli walls are kept moist by water diffusing from the surrounding cells.he walls of the alveoli are composed of a single layer of flattened epithelial cells, as are the walls of the capillaries, so gases need to diffuse through just two thin cells. The alveoli walls are kept moist by water diffusing from the surrounding cells.
The collective term for all the structural components through which respiratory gases must diffuse in order to be exchanged between the air in the alveoli and the blood; this consists of the cell membranes and cytoplasm of the type I alveolar cells, the alveolar epithelial basement membrane, the very limited amount of loose fibrous connective tissue present, if any, beneath it, the capillary basement membrane, and the cell membranes and cytoplasm of the capillary endothelial cells.