1 - Gray
2 - Green
3 - One is bleak, and without life. While the other is vibrant, and is completely opposite of the other.
I will need a story to look at to answer this...
For most of the cases, writers put rhyming lines at the end of their writing to create some sort of easier flow for the readers.
This will make the end-rhymed lines will become catchy and easier to remember for the readers
hope this helps
