1. for which of the following activities might you want to hire a chemist?
a. testing a sample of water from a well
b. finding a comet
c. examining the structure of plant cells
d. building a garage
2. which of the following procedures involves a physical change in one of the substances?
a. creating salt by reacting sodium metal and chlorine gas
b. allowing a nail to rust
c. building a model rocket propelled by mixing baking soda and vinegar
d. grinding chalk into a fine powde 3. you have three molecules of glucose (3c6h12o6). how many oxygen atoms do you have?
a. 1
b. 3
c. 6
d. 18

answer is a

explanation:

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."