<span>The common cold is regarded a viral.
Viruses: are the source of well-known diseases (colds, conjunctivitis, nasopharyngitis, bronchitis acute, flu, gastroenteritis, measles, mumps, chickenpox, <span>herpes)</span></span>
The glands of the endocrine system secrete hormones into the bloodstream to maintain homeostasis and regulate metabolism.
DNA<span> is a long polymer with deoxyribose and phosphate backbone. Having four different nitrogenous bases: adenine, guanine, cytosine and thymine. </span>RNA<span> is a polymer with a ribose and phosphate backbone. Four different nitrogenous bases: adenine, guanine, cytosine, and uracil.</span><span />
