<span>The outermost planets where so far away from the sun (many times the distance of earth) that they where invisible to the naked eye. This means that by simply looking into the eye at night it was possible to see the closer planets but not the outermost ones.</span>
I would say A, extreme jealousy. That is not a good thing in a relationship and could lead to potential abuse.
The answer is B. Symbiosis. Symbiosis is the relationship least commonly found in nature. Hope it helped you, and have a great day.
-Charlie