Why is nitrogen fixation such an important step in the nitrogen cycle?

question 7 options:

bacteria convert the fixed nitrogen back into n2.

soil nitrogen is different.

decomposers need to use nh4+.

plants can't use nitrogen in the form of n2.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance