Question

directions: use the reading and diagram to answer the following questions about the nitrogen cycle. 1. what form of nitrogen makes up most of earths atmosphere? 2. why cant most organisms use nitrogen gas (n₂) directly? 3. what is nitrogen fixation and why is it important? 4. name one natural way and one human activity that can fix nitrogen. 5. how do plants and animals get the nitrogen they need? 6. what role do decomposers play in the nitrogen cycle?

Explanation:

1. Nitrogen gas (\(N_2\)) is the form of nitrogen that makes up most of Earth's atmosphere.
2. Most organisms can't use nitrogen gas (\(N_2\)) directly because the triple bond in \(N_2\) is very stable and hard to break.
3. Nitrogen fixation is the process of converting \(N_2\) into forms (like ammonia) that organisms can use. It's important because it makes nitrogen available for biological processes.
4. A natural way is lightning (which can fix nitrogen in the atmosphere). A human activity is the industrial production of fertilizers (which involves nitrogen - fixing processes).
5. Plants get nitrogen by absorbing nitrates (from the soil, which are produced by nitrogen - fixing bacteria etc.). Animals get nitrogen by eating plants (or other animals that have eaten plants).
6. Decomposers break down dead organisms and waste products. In the nitrogen cycle, they release nitrogen (in the form of ammonia etc.) back into the environment, which can then be further processed (e.g., by nitrifying bacteria).

Answer:

1. Nitrogen gas (\(N_2\)).
2. Because the triple bond in \(N_2\) is very stable and hard to break.
3. Nitrogen fixation is converting \(N_2\) into usable forms. It's important for making nitrogen available for life.
4. Natural: Lightning. Human activity: Industrial fertilizer production.
5. Plants: Absorb nitrates from soil. Animals: Eat plants (or plant - eating animals).
6. They break down dead organisms and waste, releasing nitrogen back into the environment.