Lizards, for instance, put up with potassium-laced lettuce (6)
I believe the answer is:
geckos
'lizards' is the definition.
(I've seen this before)
'for instance put up with potassium-laced lettuce' is the wordplay.
'for instance' becomes 'eg' ('e.g.' can be a synonym of 'for instance').
'put up' says the letters should be written backwards.
'with' indicates putting letters inside.
'potassium' becomes 'k' (K is the chemical symbol for potassium).
'laced lettuce' becomes 'cos' (cos lettuce is a kind of lettuce. I am not sure about the 'laced' bit.**).
'eg' back-to-front is 'ge'.
'k' going into 'cos' is 'ckos'.
'ge'+'ckos'='GECKOS'
Can you help me to learn more?
(Other definitions for geckos that I've seen before include "Lizards with adhesive feet" , "Tropical lizards that climb walls" .)