Disease and food shortages would keep the numbers down because of the increase in life.<span />
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.
Infection<span> occurs when viruses, </span>bacteria<span>, or other </span>microbes<span> enter your body and begin to multiply. </span>Disease<span> occurs when the cells in your body are damaged as a result of </span>infection<span> and signs and </span>symptoms<span> of an illness appear. Pathogenic </span>microbes<span> challenge the immune system in many </span>ways<span>.</span>
