Which is correct?
People have been growing cotton for ages.
People have been growing cotton since ages.
"for ages"

Use 'for' with a general length of time:
he hasn't done it/it will last..... 'for weeks', 'for a long time'

Use since when referring back to a specific time in the past
'since tuesday', 'since last time'

Students: Are you brave enough to let our tutors analyse your pronunciation?

1st ans is correct

My grandparents lived in that house for ages