The first three answers are natural changes, while the last three are because of human intervention.
It is the Free trade. A typical contention against free trade is the decrease of residential employments from the expansion in imported products from global nations. Free trade is exemplified by the European Economic Area and the Mercosur, which have built up open markets.
Answer:
The bowl of ice cream contains ice cream with temperature below freezing point. A hot body contains more thermal energy than a cold body. Thermal energy only flows from a hot body to a cold body, and not the reverse.
The bowl of ice cream contain less thermal energy than it sorrounding envoirment (air and the kitchen counter), this creates a temperature gradient that forces thermal energy from the sorrounding envoirment into the bowl of ice cream because, according to thermodynamics, all bodies always tend to be in thermal equilibrium with its sorrounding. The thermal energy flows into the bowl of ice cream until it has the same thermal energy with its sorrounding; bringing the thermal gradient between them to zero.
Wow. None of these are great. However, I think that A is the best answer. If you do a biodiversity study and find there is an open niche in the ecosystem, this may indicate an opportunity for an invasive species to enter the ecosystem.
