Look into religious education examination (8)
I believe the answer is:
research
'look into' is the definition.
(researching is a kind of looking into)
'religious education examination' is the wordplay.
'religious education' becomes 're'.
'examination' becomes 'search' (search is a kind of examination**).
're'+'search'='RESEARCH'
(Other definitions for research that I've seen before include "enquiry" , "Experimentation" , "material for investigation" , "What may make you a doctor" , "Scientific investigation" .)