Which of the following is a theory for the dinosaur extinction?
1.dinosaurs were allergic to pollen
2.increased radiation levels
3.diseases from other animals
4.all of above

Increased Radiation Levels is a theory for the dinosaur extinction.

Nitrogen is one of the basic elements of  life.

Explanation:

Nitrogen is one among the four basic element of life which is a chemical element. The symbol of nitrogen is N with 7 as its atomic number. In 1772, it was isolated and discovered by Scottish physician named Daniel Rutherford.As nitrogen is an inert gas, it can be used instead of air and also reduce oxidation of materials. It is also used in the manufacture of fertilizers, explosives etc.