Tutor profile: Lucas R.
Subject: Environmental Science
What is "Green" energy?
'Green' energy comes from natural sources - sunlight, water, wind, and geothermal. These energy sources are renewable and can be reused infinitely. This is in contrast to fossil fuels (coal, natural gas), which are finite resources that take millions of years to replenish.
What is an acid?
Acids have a variety of unique characteristic that help separate them from other compounds. Put simply, an acid is any substance with a pH below 7. The pH scale is used by chemists to determine how acidic or basic (alkaline) a substance is. Acids donate hydrogen (H+) ions to a solution; the higher the concentration of H+ ions in solution, the more acidic the substance. Acids are characterized by having a sour taste, and will react with metals to form hydrogen gas. Some common examples of acids are Lemon Juice, Coca Cola, Stomach acid, and Vinegar.
Are virus's alive?
This is a complex and exciting question! In general, scientists use a list of criteria to determine whether something is living or non-living. Living things are categorized as having cells, able to reproduce, use energy, and respond to their environment. Viruses do not have cells; they have a protein coat that protects their inner genetic material. On the other hand, viruses have found methods to reproduce by inserting their genetic material into cells, which then replicate. Viruses do use energy, but only when in contact with a host cell; similarly, viruses will respond to their environment only when in contact with a host cell. When scientists apply this list of criteria, the answer to whether or not a virus is alive remains unclear; they exhibit characteristics of both living and non-living things.
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