Question

match each step in the nitrogen cycle to its description.
bacteria convert atmospheric nitrogen to ammonia plants and animals take in and use nitrogen compounds bacteria convert ammonia to nitrites and nitrates
bacteria convert nitrates into nitrogen gas bacteria break down waste products and return nitrogen to the soil
nitrification
denitrification
assimilation
nitrogen fixation
ammonification

Explanation:

1. Nitrification: This process involves bacteria converting ammonia to nitrites and then to nitrates. So match "bacteria convert ammonia to nitrites and nitrates".
2. Denitrification: Bacteria convert nitrates back into nitrogen gas, which is released into the atmosphere. So match "bacteria convert nitrates into nitrogen gas".
3. Assimilation: Plants and animals take in and use nitrogen compounds (like nitrates) to build proteins, nucleic acids, etc. So match "plants and animals take in and use nitrogen compounds".
4. Nitrogen Fixation: Bacteria (like rhizobia) convert atmospheric nitrogen (\(N_2\)) into ammonia (\(NH_3\)) or related compounds. So match "bacteria convert atmospheric nitrogen to ammonia".
5. Ammonification: Bacteria break down waste products (from plants/animals) and return nitrogen to the soil in the form of ammonia. So match "bacteria break down waste products and return nitrogen to the soil".

Answer:

• nitrification $\longleftrightarrow$ bacteria convert ammonia to nitrites and nitrates
• denitrification $\longleftrightarrow$ bacteria convert nitrates into nitrogen gas
• assimilation $\longleftrightarrow$ plants and animals take in and use nitrogen compounds
• nitrogen fixation $\longleftrightarrow$ bacteria convert atmospheric nitrogen to ammonia
• ammonification $\longleftrightarrow$ bacteria break down waste products and return nitrogen to the soil