1501. What character can be added to both of these characters to give other characters? 丘_ -> _朋

Answer:

丘  KYUU, oka - hill

朋  BOU, HOU, tomo, minata - friend

Add 山:丘+山 山+朋 

山  SAN, yama - mountain

岳  GAKU, take - mountain peak

崩  HOU, kuzu(reru), kuzu(su) - fall to pieces, collapse, demolish