Rambling rose that gives varied resistance (8)
I believe the answer is:
rheostat
'varied resistance' is the definition.
'rheostat' can be an answer for 'resistance' (rheostat is a kind of resistance). I'm not certain of the 'varied' bit.
'rambling rose that' is the wordplay.
'rambling' is an anagram indicator.
'rose'+'that'='rosethat'
'rosethat' anagrammed gives 'RHEOSTAT'.
'gives' acts as a link.
Can you help me to learn more?
(Other definitions for rheostat that I've seen before include "Current controller" , "Electrical device" , "Variable resistor" , "showing some resistance" , "Sort heat with Instrument that controls the current in an electrical circuit" .)