Which statement is a proposition?
a. she set sail on tuesday.
b. why are you late?
c. good afternoon!
d. what happened to my sandwich?

The answer is A: She set sail on Tuesday.  This statement is a proposition. The statements in B and D are interrogative sentences. The statement in C is a greeting.  A proposition is a statement or a suggestion offered for consideration.  In logic, it's an expression that may be true or false, it can be affirmed or denied. There is the purpose of determining the validity of a claim.

the statement that best explains why the tenth amendment reserves some rights and powers to states is that the framers believed in the principle of federalism. this principle says that some powers are in the hands of a centralized national government, while others are reserved for the governments of several states.

"it's more of an essay than story, but perhaps it is best described as a mood-piece: it uses a lot of musical imagery, not to mention sea imagery, religious imagery, and any other imagery that suits his purpose."