<span>Robert Hooke was the first person to see cells.</span>
The correct answer is antigens and epitope.
An antigen is a substance which triggers an immune response in an organism. This can be either a foreign substance, such as a pathogen, or a specific part of the host organism (in this case this is an autoimmune response). The presence of an antigen activates a specific part of the immune system, called antibody. Each antigen has a specific antibody, which is tailored by the immune system accordingly. More specifically, the antibody has a specific structure, called paratope, which is complementary and binds like a key to a specific structure of the antigen, called epitope.
<span>Complementary base-pair rule.</span>
Primary succession can occur in essentially lifeless areas or regions in which the soil is incapable of sustaining life as a result of such factors as lava, sand dunes, or rocks left from a retreating glacier.
Chargaff found out that t<span>he ratios of thymine and adenine were equal and the ratios of guanine and cytosine were equal. He then created the Chargaff's rule states that double stranded DNA has a 1:1 ratio between pyrimidine and purine bases. With this, </span><span>amount of guanine bases is equal to cytosine bases while the amount of adenine bases is equal to thymine bases.</span>
