Xerostomia (hypo functioning of salivary glands )
The answer that seems like would best fit this graph would be "(4)Years"
Channel protein is important because it is embedded in the membrane and it also covers the membrane. This is important because the channel must transport the micromolecules and ions in and out of the cell. Carrier proteins are important because the carrier must transport the molecule in and out of the cell.
An example of something that does not have mass would most likely be air. Because in order for something to have mass, it must take up space and have shape. Anything that you can think of that does <u>not</u> have <u>space or shape</u> does not have mass.
