What materials can be used to erase part of a document?
chemicals
eraser
sandpaper
all of the above

All of the above

Erasers are natural or synthetic substances that can be used to remove or alter the handwritten or printed material from the document. The natural materials which can be used for erasing includes the rubber, sandpaper , vinyl, plastic, or gum-like materials, whereas synthetic materials includes chemicals like acetone formulations.

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.