They can enter your blood stream (via breathing/ingesting) and once in your bloodstream they can enter cells and mutate your dna, which can cause cancer/birth defects/ reproductive harm
The pollutants in 1970 were the highest since recorded history and are declining steadily.
Before your food passes from the mouth and down your esophagus, salivary amylase, an enzyme in saliva, begins to digest the starch in your bread. That is the start of chemical digestion. ... The passage of the bolus through the esophagus to the stomach occurs by peristalsis, a series of wave-like muscle contractions.
<span> RNA was thought of as little more than a messenger between DNA and proteins, carrying instructions as messenger RNA (mRNA) to build proteins. However, RNA can do far more. It can drive chemical reactions, like proteins, and carries genetic information, like DNA. And because RNA can do both these jobs, most scientists think life as we know it began in an RNA world, without DNA and proteins.</span>
The cell membrane<span> is selectively permeable to ions and organic molecules and controls the movement of substances in and out of </span>cells<span>. The basic </span>function of the cell membrane<span> is to protect the </span>cell<span> from its surroundings. It consists of the phospholipid bilayer with embedded proteins.</span>
