Histamine is released when a cell come across an antigen
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Washington d.c is the capital of the u.s
molten rocck near ground water supplies
I believe the positive control receives a treatment with a known response, so that this positive response can be compared to the unknown response of the treatment. This is used in electrophoresis to compare the DNA strands to the DNA standard. The negative control is used when no response is expected, which is also used in the process of electrophoresis. Electrophoresis is a technique used in laboratories in order to separate macromolecules based on size. It applies a negative charge so proteins move towards a positive charge. It is sued for the analysis of both DNA and RNA.
Cartilaginous fishes have an internal skeleton made of cartilage and their skin is covered with placoid scales.
While, The bony skeleton of bony fishes is harder and heavier than cartilage. Bony fishes have either lungs or a swim bladder and hard, thin scales.
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