Q: Wolves kill many elk every year and often attack old, sick, and injured members of a herd. Which of the following best describes the role of the wolves in the wolf-elk relationship? OPTIONS:
- competitor
- host
- parasite
- predator
A: predator

Q: Use The Periodic Table of the Elements and the information below to answer the question. Magnesium metal (Mg) is grayish-white in color and reacts actively with water. Fluorine (F2) is a greenish-yellow gas at room temperature and is a member of the halogen family. These two elements react to produce magnesium fluoride (MgF2), a chemical commonly used in making windows and lenses. How do the elements magnesium (Mg) and fluorine (F2) produce the compound magnesium fluoride (MgF2)? OPTIONS:
- by nuclear connection
- by physically combining
- by magnetic connection
- by chemically combining
A: by chemically combining

Q: A drain cleaner consists of sodium hydroxide and aluminum. When the drain cleaner is added to water, bubbles of hydrogen are produced, and the solution becomes very hot. Which of these best describes what happens to form the bubbles when the cleaner is added to water? F OPTIONS:
- chemical reaction
- Condensation
- A physical change
- Evaporation
A: chemical reaction

Q: In order to survive, all organisms must have OPTIONS:
- chlorophyll
- carbon dioxide
- energy
- blood
A:
energy