A lichen is a combination of fungus and algae that lives on the sides of trees, rocks, and other materials. The fungus provides the algae with water and minerals and the algae uses the water and minerals to make food for both organisms. What BEST describes the ecological relationship in this example? A. A competition relationship, because the fungus competes with the algae for the same limited resources.

B. A commensalism relationship, because the fungus benefits and the algae is neither helped nor harmed.

C. A mutualism relationship, because the fungus and algae both benefit from the relationship.

D. A predator-prey relationship, because the fungus benefits from the relationship while the algae is consumed as food.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.

b.have there own function.