Answer:
The answer is <em><u>D.
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Explanation:
Viruses can evade the processing and presentation of antigens, for example by interfering with the expression of MHC class I proteins, although this increases their susceptibility to be detected by natural killer cells (NK). However, some members of the herpesvirus, papillomavirus, retrovirus, poxvirus and flavivirus families have also developed strategies to escape the attack of NK cells and promote their survival, inhibiting cell apoptosis. Finally, some pathogens often change surface antigens frequently, as in the case of influenza viruses (orthomyxovirus).
The human immunodeficiency virus (HIV) affects CD4 + T cells and degrades the host's ability to counterattack with a strong cell-mediated immune response. There are so many tactics of immune evasion used by HIV, which have so far hindered the development of an effective vaccine.
Answer:
Voluntary muscles mean under conscious control and skeletal muscle is consciously controlled, unlike involuntary muscle, the ly are controlled by the autonomic nervous system.
Answer:
Oxygen Depletion
Explanation:
In addition to the eutrophication of water bodies, wastewater effluents also contribute to another process of deoxygenation. The biological (bacterial) breakdown of organic solids in the effluent also consumes dissolved oxygen – the biological oxygen demand (BOD). In addition, the degradation of chemicals in the effluent removes oxygen from the water through chemical reactions – the chemical oxygen demand (COD).
As was previously mentioned, the loss of dissolved oxygen in the water can result in serious immediate, short-term, or long-term consequences to aquatic life. Fish survival is particularly affected by low oxygen levels. Decreased disease resistance, reduced growth, altered swimming behaviour, feeding, migration, and reproduction, increased threat of predation, and even rapid death are some of the effects of low dissolved oxygen concentrations.
Low oxygen levels can also alter the kinds of species present in the ecosystem. With a change in food supply, some populations of species decrease, while others increase. Fish such as whitefish, walleye, and pike may disappear, while bottom-feeding fish such as carp may increase in number.
Answer: Precipitation occur more frequently than evaporation over land.
Explanation:
Precipitation refers to the water vapour that fall from the atmosphere in form of rain, snow, sleet, freezing rain or hail. It delivers water from the atmosphere to the Earth. Precipitation occur more on the land than evaporation, most water that teaches the surface of the Earth fall back on the land and fill the inland water, rivers , storages,e.t.c.
Evaporation occur frequently in the ocean because it is expose to the sun and most water that is evaporated from the ocean fall back to the ocean as precipitation.
