Plants get nitrogen from
the air
water
the soil

the soil

The nitrogen used by most plants is derived from soil.

Nitrogen is an important element. It is needed by organisms to produce amino acids 

Nitrogen is made usable for plants by bacteria which change nitrogen to  ammonium.

Ammonium  gets changed to nitrates by bacteria in a process called nitrification, which takes place in soil.

Nitrates is the form that plants can absorb. They absorb it through their roots and use it to make amino acids, nucleic acid and chlorophyll.

The answer you are looking for is the soil.

Explanation:

Because yes :D

answer: angiosperms

dicots

angiosperms are highly evolved plants, they produce seeds which are enclosed within in a carple. these are the largest group of plants on earth. they include trees, shrubs, herbs and small flowering plants. angiosperms exhibit a flowering stage in their life cycle. the flower serves the function of reproduction and fruit formation in majority of angiosperms. dicot is the term used to describe flowering plants that have two seed leaves. dicots are plants which develop seeds which split into two parts called cotyledons. each cotyledon contains one embryo.

here, a small purple flower development indicates that the plant belongs to angiosperms and having two embryonic leaves indicates it belongs to dicots.