Answer:
B)attach specifically to host cell receptors
Explanation:
Viral spikes are one of the envelope proteins. These proteins are coded for by viral genes. Viral spikes project from the envelope surface. They are also called peplomers. One of the functions of these spikes is to specifically interact with the receptors present on the surface of the host cell to mediate the attachment of the virus to the host cell surface. Viral spikes and the host cell surface receptors are complementary to allow their specific binding. For example, the spike protein of the SARS-coronavirus bind specifically to the human host cell receptor ACE2.
The connection between the political situations in Iran and Nicaragua during the mid-1980s was both countries fought the USSR with weapons supplied by the United States. The correct answer is D.
An engineering cycle is meant to assess the environmental impacts in relation to economic impacts on a product. The assessment is the whole life cycle of a product consisting of production, use phase and end of life. It's important because it helps mold the standard of living for generations to come and be sustained indefinitely. It protects against negative environmental factors but also reduces the cost of production for business', also.
Decomposers also break down the bodies of dead organisms resulting in nitrogen being returned to the soil as ammonia. In some conditions denitrifying bacteria in the soil break down nitrates and return nitrogen to the air.
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Explanation:
Porosity depends on the size, shape, and mixture of grains and particles that compose soil and rock. For instance, small particles such as clays can compact more closely together, reducing the amount of porosity. However, larger particles such as sand and gravel will have more spaces available between them.
