Well, to answer your first question, Because there are places on Earth that are both biologically rich — and deeply threatened. For our own sake, we must work to protect them. and for your 2nd question, 3 characteristics of magnetic reversal are: field, bar magnet, and molten material. Hope this helps
Transcription is the correct answer
Answer:
its <em>C) TGTCAGCTACGT</em>
friction is a force that opposes motion and significantly slows the cars as they move on the track. While it is easy to believe that friction is bad for the ride, it is one of the forces engineers consider in ensuring passengers have a safe ride.
The immune system<span> recognizes HIV by its antigen shape. But, just when the immune system recognizes one shape, HIV may multiply and change the shape of its antigen. </span><span>HIV can "hide" from the immune system for a long time. </span><span>When HIV infects a cell the </span>virus<span> may make more viruses and infect more cells or lie quietly in a cell for a long time. If HIV doesn't reproduce, the immune system can't find it and destroy it. </span>HIV destroys the immune system. The Immune system consists of Innate Immunity and Humoral Immunity Innate Immunity is Non-specific Immunity, whereas Humoral Immunity is specific Immunity. T-cells produce Cell-Mediated Immunity and B-cells produces Humoral Mediated Immunity. <span>As HIV destroys more and more helper T cells, the immune system begins to break down. </span> Finally the immune system can no longer kill HIV or any other invading germs and a person infected with HIV is diagnosed with AIDS.
