An organism's environment can affect its appearance. Ex. tiger salamanders deprived of iodine looked completely different and were at first considered another species. Later found to be the environment that caused the change.
example of active transport is the sodium-potassium pump, which moves sodium ions to the outside of the cell and potassium ions to the inside of the cell.
<em>The three groups of organisms have the capability to cause different diseases in humans and other animals. The specific ones among them that can cause diseases are said to be pathogenic while those that are incapable of causing diseases are said to be non-pathogenic.</em>
