All those in favour of the leading agent behind The Rising (5)
I believe the answer is:
yeast
'all those in favour' is the definition.
I can't judge whether this definition defines the answer.
'the leading agent behind the rising' is the wordplay.
'the leading' means one lot of letters go next to another.
'behind' says to take the final letters.
'the rising' becomes 'yeas' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The last letter of 'agent' is 't'.
't' put after 'yeas' is 'YEAST'.
'of' is the link.
Can you help me to learn more?
(Other definitions for yeast that I've seen before include "Substance used to raise dough etc" , "Brewer's agent" , "Leavening agent in bread-making" , "Brewing agent" , "What makes bread rise" .)