The human immunodeficiency virus (HIV) that causes the disease known as aids selectively infects helper T cells (CD4+).
This retrovirus also infects macrophages and dendritic cells. When CD4+ T cell numbers decrease below a critical level (due to the killing of this cells with different mechanisms), cell-mediated immunity is lost. As a result, the body becomes progressively more susceptible to infections, leading to the development of AIDS.
<span> HIV can be transmitted only via body fluids like blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk, which means that people usually get or transmit HIV through sexual behaviours and use of the needle. For HIV infection, these fluids must come in direct contact with a mucous membrane or damaged tissue. Another way is to be directly injected into the bloodstream (from a needle for example).</span>
Hi,
I think the answer you are looking for is “acid compound”.
I hope this helps. If you’d like further explanation please let me know. Also, English is not my first language, so I’m sorry for any mistakes.
Answer:
1. The respiratory system allows us to breathe . They bring oxygen into our body and remove carbon dioxide from the body .
2. Tiny hairs called cilia protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.
3. The throat (pharynx and larynx) is a ring-like muscular tube that acts as the passageway for air, food and liquid. It is located behind the nose and mouth and connects the mouth (oral cavity) and nose to the breathing passages (trachea [windpipe] and lungs) and the esophagus (eating tube).
4. The main function of the epiglottis is to seal off the windpipe during eating, so that food is not accidentally inhaled.
5. The heart pumps blood to the lungs for oxygenation and the lungs then give the heart back oxygen rich blood to be transmitted to the whole body
Explanation:
plss mark brainliest
<span>I believe the answer is: D. proteins
The main functions of these proteins is to allow specific substance to pass through the membrane of the cells which needed for the energy formation for cells'functions.It created through the combination of more than 20 amino acids with different functions.</span><span />
