What is a general representation of a secondary amine?

general representation of a secondary amine is .

Explanation: Ammonia is . When one or more H atoms of ammonia molecule are replaced by alkyl groups then the newly formed compounds are known as amines.

If one of the H atom from ammonia molecule is replaced by an alkyl group then we call it primary amine. It's written as .

If two H atoms of ammonia molecule are replaced by same or different alkyl groups then we call it secondary amine. It's written as  and if all the three H atoms of ammonia molecule are replaced by same or different alkyl groups then we call it tertiary amine. It is written as .

So, the general representation of a secondary amine is .

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.