The early immune response to HIV-1 infection is likely to be an important factor in determining the clinical course of disease. Recent data indicate that the HIV-1 quasispecies that arise following a mucosal infection are usually derived from a single transmitted virus. Moreover, the finding that the first effective immune responses drive the selection of virus escape mutations provides insight into the earliest immune responses against the transmitted virus and their contributions to the control of acute viraemia. Strong innate and adaptive immune responses occur subsequently but they are too late to eliminate the infection. In this Review, we discuss recent studies on the kinetics and quality of early immune responses to HIV-1 and their implications for developing a successful preventive HIV-1 vaccine.
The respiratory structure that contracts and relaxes to allow air to flow in and out of the lungs is option(c) i.e, the diaphragm.
<h3>What is
the diaphragm?</h3>
The diaphragm, a delicate skeletal muscle that separates the chest from the belly, is located at the base of the chest. When you breathe in, it flattens and shrinks. As a result, the lungs experience a vacuum effect that draws air in. The diaphragm relaxes and the air is forced out of the lungs when you exhale.
signs of diaphragm issues:
- Acid reflux, heartburn, coughing, and difficulty swallowing.
- alterations to skin tone (skin may turn blue).
- rapid heartbeat, pressure in the chest, and/or breathing difficulties (especially when lying down).
- Headaches.
- Hiccups that persist or recur frequently.
Patients who need surgery for conditions affecting the chest, including diaphragm issues, are treated by a thoracic surgeon.
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the answer is C. water enters the cells in the skin
A group of atoms such as OH on a larger compound is called a functional group.