What causes sudden feeling of sadness and anxiousness ?

One possible cause of persistent sadness could be depression

Explanation:

anything could trigger the sadness or anxiousness in a person, maybe thinking of a deceased loved one, a sudden break up, stage fright, anything

the index of refraction of the second medium is higher. i just took the test trust me !

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.