Abundant most likely means: more than sufficient without being excessive. plentiful implies a great or rich supply.
Os anglo-americanos normalmente falam principalmente em inglês, mas alguns também podem falar espanhol. Todo o resto realmente depende da pessoa, seja religião, emprego ou personalidade.
B; As far as the relation between humans and the environment, it is obvious how much they relied on it. Not only as a food source, but for economic growth and sustainability as well. The other answers make valid points but in the context of this question, the only one that even mentions the relation is B.