Groups causing near chaos at some stage? (6)
I believe the answer is:
genera
'groups' is the definition.
(more than one biological genus)
'near chaos at some stage?' is the wordplay.
I cannot quite see how this works, but
an anagram of 'near' is 'nera' which is within the answer.
The remaining letters 'ge' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'causing' acts as a link.
Can you help me to learn more?
(Other definitions for genera that I've seen before include "Orders with common characteristics" , "Biological groups" , "Groups with common characteristics" , "Sorts" , "Groups between family and species (biology)" .)