Question: Answer the following question given this paragraph: Chemists need to be concerned with the rates at which chemical reactions occur. Rate is another word for speed. If a sprinter takes 11.0 s to run a 100 m dash, his rate or speed is given by the distance traveled divided by the time. Q: Distance traveled divided by time yields what measurement, which is another word used to describe the speed of a chemical reaction? A:
OPTIONS:
- flow
- displacement
- acceleration
- rate
Answer: rate

Question: Answer the following question given this paragraph: Prokaryotes and the Nitrogen Cycle Nitrogen is a very important element for life because it is part of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds to ammonia, ammonium ions, nitrate, nitrite, and nitrogen gas by myriad processes, many of which are carried out only by prokaryotes. As illustrated in Figure 22.19, prokaryotes are key to the nitrogen cycle. The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen from the air, but this nitrogen is not usable by plants, which are primary producers. Gaseous nitrogen is transformed, or "fixed" into more readily available forms such as ammonia through the process of nitrogen fixation. Ammonia can be used by plants or converted to other forms. Another source of ammonia is ammonification, the process by which ammonia is released during the decomposition of nitrogen-containing organic compounds. Ammonia released to the atmosphere, however, represents only 15 percent of the total nitrogen released; the rest is as N2 and N2O. Ammonia is catabolized anaerobically by some prokaryotes, yielding N2 as the final product. Nitrification is the conversion of ammonium to nitrite and nitrate. Nitrification in soils is carried out by bacteria belonging to the genera Nitrosomas, Nitrobacter, and Nitrospira. The bacteria performs the reverse process, the reduction of nitrate from the soils to gaseous compounds such as N2O, NO, and N2, a process called denitrification. Q: Prokaryotes and the nitrogen cycle nitrogen is a very important element for life because it is part of proteins and this? A:
OPTIONS:
- nuclear forces
- nerve cells
- molecules
- nucleic acids
Answer: nucleic acids

Question: Answer the following question given this paragraph: The new cells gradually move up through the epidermis toward the surface of the body. As they move, they produce the tough, fibrous protein called keratin. Q: What is the most common cause of lung cancer? A:
OPTIONS:
- coal smoke exposure
- restaurant smoke exposure
- tree smoke exposure
- tobacco smoke exposure
Answer:
tobacco smoke exposure