Last chance! Terribly cool soldier about to start learning about environmental relationships (10)
I believe the answer is:
ecological
'start learning about environmental relationships' is the definition.
I can't judge whether this definition defines the answer.
'last chance terribly cool soldier about' is the wordplay.
'last' indicates one should take the final letters.
'terribly' indicates anagramming the letters.
'soldier' becomes 'GI' (GI can mean a US soldier).
'about' becomes 'cal' (I can't justify this - if you can you should give a lot more credence to this answer).
The last letter of 'chance' is 'e'.
'cool' is an anagram of 'colo'.
'e'+'colo'+'gi'+'cal'='ECOLOGICAL'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for ecological that I've seen before include "Green" , "Gaelic cool (anag.)" .)