The most remarkable thing that can be readjusted by environmental cues is our body clocks
I think the subject and the compliment do not match and look awkward. What do you think?
The most remarkable thing that can be readjusted by environmental cues is our body clocks
I think the subject and the compliment do not match and look awkward. What do you think?
The subject "thing" is singular, and so "is" is correct. It is grammatical.
The number of the predicate is not relevant.
For example:
Our team is 20 players.
(in American English)
The problem is Tom, Dick, and Harry.