*Question*
Answer the following question given this paragraph: A period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons. Period 1 has only two elements (hydrogen and helium), while periods 2 and 3 have 8 elements. Periods 4 and 5 have 18 elements. Periods 6 and 7 have 32 elements because the two bottom rows that are separated from the rest of the table belong to those periods. They are pulled out in order to make the table itself fit more easily onto a single page. Q: A period is a horizontal row of the what? Choices: - cycles table - phases table - species table - periodic table A:
**Answer**
periodic table

*Question*
Answer the following question given this paragraph: Vertebrates have an adaptive immune system. The immune system is the organ system that defends the body from pathogens and other causes of disease. Being adaptive means that the immune system can learn to recognize specific pathogens. Then it can produce tailor-made chemicals called antibodies to attack them. This allows the immune system to launch a rapid attack whenever the pathogens invade the body again. Q: Which organ system defends the body from pathogens and other causes of disease? Choices: - digestion system - nervous system - respiratory system - immune system A:
**Answer**
immune system

*Question*
Answer the following question given this paragraph: Q: What evolutionary process does not favor altruistic behavior that causes the death of the altruist? Choices: - flow selection - characteristic selection - random selection - natural selection A:
**Answer**
natural selection

*Question*
Answer the following question given this paragraph: Saturated and Unsaturated Fatty Acids. Saturated fatty acids include arachidic, stearic, and palmitic fatty acids. Unsaturated fatty acids include all the other fatty acids in the figure. Notice how all the unsaturated fatty acids have bent chains, whereas the saturated fatty acids have straight chains. Q: Arachidic, stearic, and palmitic fatty acids are examples of what type of fatty acid? Choices: - neutral - integral - compacted - saturated A:
**Answer**
saturated