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>
Use the following terms to describe in detail how you visually perceive an object that you can see right now.
Answer: To see for example an apple first light that passes through the pupil is eventually reflected on the pupil, activating neurons in the retina. light waves that were reflected off the apple are changed into neural impulses (transduction) at the point of the retina, where neurons fire in response to light waves. Action potentials are released when neurons fire, sending an electrical charge through the neuron. Excitatory neurotransmitters are released when the action potential reaches the axon terminal, and that these neurotransmitters increase the chances that the next neuron will fire. Of course the neural message from the retina first passes through the thalamus, and then the thalamus routes the impulse elsewhere in the brain.
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<span>presence of protoplasm, self built organisms, self repair, reproduction and various life process like metabolism, nutrition, respiration, exchange of material, transportation, excretion and irritability.</span>
Answer:
starch
Explanation:
In the presence of sunlight ,water,and oxygen the photosynthesis occurs .
As the by product of photosynthesis the starch or glucose(C6H12O6) is produce.
