Question

1. transpiration
2. precipitation
3. nitrogen fixation
4. assimilation
5. denitrification
6. fossil fuels
7. combustion
8. erosion
9. respiration
10. photosynthesis
11. biogeochemical cycle
12. condensation

a. co₂ enters plants during this process.
b. absorption of nitrogen by plants.
c. the burning of fossil fuels.
d. process in which bacteria combine nitrogen with hydrogen to form ammonia in the soil.
e. a cycle in which a substance enters a living organism for a time then returns to the nonliving environment.
f. the evaporation of water from the leaves of plants.
g. rain or snow.
h. carbon - based materials made of decayed plants and animals - used for fuel.
i. bacteria convert nitrogen - based compounds into nitrogen gas.
j. vaporized water forms clouds during this process.
k. the breakdown of limestone; returns co₂ to the water.
l. exhaling co₂ and returning it into the atmosphere.

Explanation:

1. Transpiration is the process by which plants lose water vapor through their leaves. So a. CO₂ enters plants during this process is incorrect. It is mainly water - vapor loss and gas - exchange related to photosynthesis and respiration occurs, not significant CO₂ entry in this process.
2. Precipitation is rain or snow, so g. Rain or snow is the correct description.
3. Nitrogen fixation is the process where bacteria combine nitrogen with hydrogen to form ammonia in the soil, so d. Process in which bacteria combine nitrogen with hydrogen to form ammonia in the soil is correct.
4. Assimilation is a cycle in which a substance enters a living organism for a time then returns to the non - living environment, so e. A cycle in which a substance enters a living organism for a time then returns to the nonliving environment is correct.
5. Denitrification is when bacteria convert nitrogen - based compounds into nitrogen gas, so i. Bacteria convert nitrogen - based compounds into nitrogen gas is correct.
6. Fossil fuels are carbon - based materials made of decayed plants and animals used for fuel, so h. Carbon - based materials made of decayed plants and animals used for fuel is correct.
7. Combustion is the burning of fossil fuels, so c. The burning of fossil fuels is correct.
8. Erosion is not related to the breakdown of limestone returning CO₂ to water.
9. Respiration is exhaling CO₂ and returning it into the atmosphere, so l. Exhaling CO₂ and returning it into the atmosphere is correct.
10. Photosynthesis is not related to vaporized water forming clouds.
11. Biogeochemical cycle is not related to the evaporation of water from the leaves of plants.
12. Condensation is vaporized water forming clouds, so j. Vaporized water forms clouds during this process is correct.

Answer:

1. None of the above
2. g. Rain or snow
3. d. Process in which bacteria combine nitrogen with hydrogen to form ammonia in the soil
4. e. A cycle in which a substance enters a living organism for a time then returns to the nonliving environment
5. i. Bacteria convert nitrogen - based compounds into nitrogen gas
6. h. Carbon - based materials made of decayed plants and animals used for fuel
7. c. The burning of fossil fuels
8. None of the above
9. l. Exhaling CO₂ and returning it into the atmosphere
10. None of the above
11. None of the above
12. j. Vaporized water forms clouds during this process