<span>The most crucial principle of ELISA (enzyme-linked immunosorbent assay) is a highly specific antibody-antigen interaction.</span>
ELISA is a biochemical technique used to detect the presence of an antibody or an antigen in the biological sample. Simply described, in an ELISA, an antigen is immobilized on a solid surface and then a specific antibody is applied over the surface so that it can bind to the antigen. The antibody is usually linked to an enzyme, and in the final step, a substrate for that enzyme is added. The enzyme can convert it to some detectable signal, most commonly a color change. <span>Medical usage of ELISA is in the diagnosis of HIV infection, pregnancy tests, measurement of cytokines…</span>
Answer:
The tropical regions are subjected to extreme changes of season. The polar regions were populated earliest in the history of Earth.
Three layers. The epidermis is the top layer of skin. This layer is for making new skin cells, provides a waterproof barrier, gives skin its color and is your protective layer. The dermis which is responsible for supply blood to your skin, hair growth, and the production of sebum (oil) and sweat. Lastly, the hypodermis which is basically made of connective tissue and fat and good for regulating your body temperature (1, 2, 3).
The correct answer is chromosomal mutations
