Answer:
a desire to bypass Muslim merchants in trade with Asia and Africa.
Explanation:
Portuguese and Spanish overseas exploration took place during the 1400's and it was mainly motivated because both Portugal and Spain were looking for a fastest route to get to Africa (Portugal) and Asia (Spain). Back in the day, the muslim merchants had a lot of control over these routes and these countries were looking for a way to get there faster. Actually, Columbus got to America while he was trying to find a route to India.
Therefore, both Portuguese and Spanish overseas exploration was motivated by a desire to bypass Muslim merchants in trade with Asia and Africa.