Answer the following question given this paragraph: The oxygen atoms, however, form oxygen gas, which is a waste product of photosynthesis. The oxygen given off supplies most of the oxygen in our atmosphere. Before photosynthesis evolved, Earth's atmosphere lacked oxygen altogether, and this highly reactive gas was toxic to the many organisms living at the time. Something had to change! Most contemporary organisms rely on oxygen for efficient respiration. So plants don't just "restore" the air, they also had a major role in creating it!. Q: Plants not only contribute food but what else for organisms? Choices: - dioxide - hydrogen - carbon - oxygen A:
oxygen

Answer the following question given this paragraph: Acidophiles are organisms that "love" acids. They live in very acidic environments, such as acid mine drainage. They are also found near vents of volcanoes. The most acidophilic archaeans can thrive at negative pH values. No other organisms can survive in such acidic conditions. Q: Organisms that "love" acids are known as what? Choices: - acidophobes - acidic - acid heads - acidophiles A:
acidophiles

Answer the following question given this paragraph: The smallest particle of an element that still has the element's properties is an atom . All the atoms of an element are alike, and they are different from the atoms of all other elements. For example, atoms of gold are the same whether they are found in a gold nugget or a gold ring (see Figure below ). All gold atoms have the same structure and properties. Q: What is the smallest particle of an element that still has the element's properties? Choices: - an ion - a nucleus - an electron - an atom A:
an atom

Answer the following question given this paragraph: DNA's three-dimensional structure is a double helix. The hydrogen bonds between the bases at the center of the helix hold the helix together. Q: What type of bonds between the bases at the center of the dna double helix hold the helix together? Choices: - helium bonds - ionic bonds - electron bonds - hydrogen bonds A:
hydrogen bonds