Could it support a partial variation in sea level? (5)
I believe the answer is:
easel
'could it support a partial' is the definition.
I can't judge whether this defines the answer.
'variation in sea level?' is the wordplay.
'variation in' is an anagram indicator.
'level?' becomes 'el' (I am not sure about this - if you are sure you should believe this answer much more).
'sea' with letters rearranged gives 'eas'.
'eas'+'el'='EASEL'
Can you help me to learn more?
(Other definitions for easel that I've seen before include "Tripod for an artist" , "Painter's frame" , "Picture stand" , "Painter's support" , "Supporter for the artist" .)