Formal.
As far as I know, there is no such thing as either standard or practiced diction. Informal is the way you communicate with your friends, for instance, which is not how you would write a thesis paper, legal document, etc.
Answer:
Exposition. You get an idea of what kind of guy the man is from the way he is being described.
Explanation:
The little brown bat seeks out audiences other than the mocking bird because the mockingbird understands the technical aspects of poetry but doesn't feel the emotional impact. The correct answer is B.
Answer:
It has grown more than 250,000 square miles over the last 53 years.
Explanation:
The context clue refers to the information that the author provides to help readers understand the meaning of a word. In this case, following the word expanding, the author writes another sentence to describe and support his idea that the Sahara is enlarging. Besides, it is later mentioned that it will be bigger than Antarctica.