They enable reproduction of European goods and US phones (3,5)
I believe the answer is:
egg cells
'they enable reproduction' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'european goods and us phones' is the wordplay.
'european' becomes 'e' (abbreviation e.g. EU).
'goods' becomes 'gg' (an abbreviation for good written twice).
'and' means one lot of letters go next to another.
'us phones' becomes 'cells' (I am not sure about this - if you are sure you should believe this answer much more).
'e'+'gg'+'cells'='EGG-CELLS'
'of' is the link.
Can you help me to learn more?
(Another definition for egg cells that I've seen is " Female gametes - ova".)