The responses observed in type IV hypersensitivities result from the action of T cells and phagocytes.
Hypersensitivity IV type, also called delayed-type hypersensitivity (DTH), involves T cell-antigen interactions that cause activation and secretion of cytokines. This type of hypersensitivity requires sensitized lymphocytes that respond 24–48 hours after exposure to soluble antigens. A type IV hypersensitivity reaction is a cell-mediated reaction that can occur in response to contact with certain allergens, resulting in what is called contact dermatitis, or in response to certain diagnostic procedures such as the tuberculin skin test. Certain allergens need to be avoided to treat this condition. Type IV hypersensitivity response is observed results from the action of T cells and macrophages while other types are mediated by antibodies. This reaction occurs at least 1–3 days after the initial exposure. Type IV hypersensitivity is the mechanism of many autoimmune disorders.
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Answer:
The correct answer is A. Fossil fuels are cheaper than alternative forms of energy
Explanation:
Fossil fuels are made from organic matter of dead animals and mainly plants who were buried in the soil over hundred and thousand of years. We use fossil fuels because they are the best source to provide energy in the current time.
Fossil fuels are easily available and are present in very large amount which is the main reason for it to be cheaper. Fossil fuels like coal, petroleum or natural gas are more cheaper and efficient than alternative forms of energy like solar or wind energy.
But in future these fossil fuel will not be there and alternative forms of energy will become the primary and cheaper source of fuel.
<span>The answer is free-market. One view is that a free market is a framework in which the costs for products and enterprises are controlled by the open market and purchasers, in which the laws and strengths of free market activity are free from any intercession by an administration, value setting syndication, or other specialist.</span>
jagged line of protein discs which attach thin filaments from
end to end, trace the boundary where
sarcomeres connect, thick type of
smallest muscle unit: composed of staggered arrays of many myosin molecules
which interact with actin when calcium is present.
