Reread lines 251-256. what does the author convey with the statement, "the light goes out for the marsh.

The light, then, is the light that her friendship brought to his life. Her friendship is light -- it is happiness and is joy to Tom. When the two friends stop hanging out, the light goes out of the marsh. The author is saying the joy has gone out of Tom's life. 

Ruby becomes disappointed with Tom when the hose leaks and Ruby can no longer dive. The two stop hanging out, and Tom loses her friendship.

faulty parallelism is a construction in which two or more parts of a sentence are equivalent in meaning but not grammatically similar in form.

the correct version of this faulty parallelism in the sentence is:

the hikers knew that the hike was six miles, that it usually required the entire day, and it would not be wise to start after 10: 00 a.m.

the problem is the last sentence, the first two have a basic subject+verb+object structure.

so, to give a proper balance to the structure, or better said, to give a parallel structure, we must write a basic s+v+o structure in all three sentences:

the hikers knew that the hike was six miles, that it usually required the entire day, and it would not be wise to start after 10: 00 a.m.

can i see the painting?