Farmer Fran sprays her sugarcane field with a highly effective pesticide called 'Bayou Bug Blast'. For five years the pesticide works without a hitch, effectively killing almost all of the bayou weevils trying to eat Farmer Fran's crop. However, during the 6th year, some of the crop takes a hit. During the 7th year, she loses half of her crop, and during the 8th year, she loses almost the entire cane field to bayou weevils, despite using twice the usual dose of Bayou Bug Blast. What happened?

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.

the correct answer is d