4. what do denitrifying bacteria do?

Denitrifying bacteria form a necessary part of the process known as denitrification as part of the nitrogen cycle which consists of the ongoing processes that Nitrogen has to undertake as it is the largest gas compound in the atmosphere.

Explanation:

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

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.