Answer:
Physical characteristics.
Explanation:
She knew what type of birds they were based on their physical characteristics.
She didn't see their nests, or see them eat, and she didn't test and analyze their genetics, so a is the correct option.
Answer:
Honestly, I would join them
The use of civil service exams
A free-trade zone is by definition “a place where trade is left to happen without tariffs(tax on imports/exports), quotas, or other restrictions”. An example of a free-trade zone is the European Union. There are no tariffs, quotas, or other restrictions placed on trading within the EU countries (they even share a currency). This allows for them to place products at a cheaper price for good quality and still get enough money to grow wealth within the different countries.