You know, some young adults have land in Africa (5)
I believe the answer is:
kenya
'land in africa' is the definition.
(country in Africa)
'you know some young adults' is the wordplay.
I cannot quite see how this works, but
'you' could be 'ya' (non-standard spelling as in 'see ya later') and 'ya' is located in the answer.
'know' could be 'ken' (Scottish term meaning to know) and 'ken' is present in the answer.
No letters remain.
This explanation may well be incorrect...
'have' is the link.
Can you help me to learn more?
(Other definitions for kenya that I've seen before include "Republic in East Africa" , "Its capital is Nairobi" , "East African country" , "East African republic" , "state?" .)