The DNA molecule is a double helix, shaped like a twisted ladder.
Metamorphic rock; because a rock that has added heat or pressure is metamorphic because it’s been chemically and physically changed
Answer:
A downhill
Explanation:
A runoff happens when water drags sediment from a rock over a sloping terrain. Thus, water drags the eroded fragments of a rock in favor of gravity, pushing these fragments downwards. This is very common in mountainous and steep regions, without vegetation cover, where erosion caused by runoff is very high.
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.
