The hot, humid weather made the work exhausting.
The early goal of Portugal during the Age of Exploration was to look for a naval route going to India. The land routes were blocked by the Ottoman Empire which hindered the trade in the Far East. India was then considered the Portuguese state and it was founded six years after the Portuguese explorers found the route to India.
Any of these will be the answer!
Answer:
<em>improved seafaring technologies</em>
