This is the correct sentence:
- My mom suggested keeping the surroundings clean and green.
It's correct to say keeping and not keep because you have to form the sentence using suggest + the verb with ing (keep + ing: keeping).
I was able to find the instructions to complete the exercise online: Write sentences using suggest + V-ing or suggest + clause with should.
Check more information here https://brainly.com/question/18900627?referrer=searchResults
