Answer:
The correct answer is "secondary succession, an ecological succession step where an area previously occupied by living beings is disrupted".
Explanation:
In ecological succession, an ecosystem changes and develops through a series of steps. The first step, is the primary successional stage where rocks or other sedimentary structures are colonized by microorganisms. The second step, where the ecosystems changes towards a relatively-stable mature stage, occurs when an area previously occupied by living beings is disrupted. This step is named secondary succession, and the most clear example of this phenomena occurs when wildfire clears oak and hickory forests.
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>
<span>They are Carbohydrates.</span>
Answer:
In the case of catalase, the optimum pH is approximately pH 7.0. That is, catalase works best at a neutral pH. If the solution is too acidic (low pH value) or too basic (high pH value) the catalase is inactive and no longer functions as an enzyme.
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Explanation:
