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.
"The Huna People, also known as Huns, invaded Gupta territory and caused significant damage to the empire. The Gupta Empire ended in 550 CE, when it disintegrated into regional kingdoms after a series of weak rulers and invasions from the east, west, and north."
If possible I'd say all of them except the fourth one down (parts of ecosystems are independant) but if not I'd say the most valid one is the second one down (healthy ecosystems help animals)
Plessy v ferguson!! i think anyways it established the "separate but equal" thing