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>
Answer:
Oxygen and nitrogen
Explanation:
Oxygen and nitrogen are very electronegative than any other element in the periodic table hence they have more tendency to attract an electron towards itself
The answer is b thank and rate my answer for 30 points they come in in 35 minutes
Answer:
680
Explanation:
When the P680 special pair of photosystem II absorbs energy, it enters an excited (high-energy) state. Excited P680 is a good electron donor and can transfer its excited electron to the primary electron acceptor, pheophytin.
Answer:
The pathway of information through the neuron is based in the connection of axons with other neurons, favoring the conduction of information from one place to another of the nervous system. The way in which a neuron communicates with another, with a receptor or an effector is called synapse.
Explanation:
Neurons are the specialized cells that allow the function of the nervous system, given by the transmission of information in the form of nerve impulses. The way in which information is transmitted by neurons depends on the connection that exists between neurons, by their axons and dendrites, or between enurons and specialized structures such as receptors and effectors.
When a stimulus reaches a receptor, it connects with the neuron that carries the information by afferent pathway to the central nervous system. Once the information is processed, a response is elaborated that travels through the neurons by efferent pathway to an effector cell.
Synapses are simply the connection that exists between neurons, through their axons, or from these cells to the receptor or effector structures. Synapses are located between one neuronal axon and another, or between axons and receptors or effectors, and occur through electrical signals or chemical mediators called neurotransmitters.
