Should I use adjective or adverb?

[GuilhermeRM]

The study research reveals startling proofs of constant changing seafloor that [...]
The study research reveals startling proofs of constantly changing seafloor that [...]

I thought ''changing'' was a noun, but my answer paper says it is participle, which demand an adverb modifier. Could anyone explain why? Thank you.:up:

 

[SoothingDave]

If you are describing an action, then use an adverb. How is it changing? It is changing constantly.

 

[GuilhermeRM]

May I use constant if ''changing'' is an adjective?

 

[5jj]

May I use constant if ''changing'' is an adjective?

No. the adverb constantly would be used to modify an adjective.