How close are two animals?

Six animals are listed with six ranks, from the kingdom to the genus. You will find the lowest rank that two animals share, the closest relative of the house cat, and the animals that share only the kingdom with it. Then the program draws the shared ranks.

The idea. Go down the two lists together. The last rank before the first difference is the lowest shared rank. A lower shared rank means a closer relation.

Your tasks.

1. In lowest_shared, return the name of the lowest rank that a and b share, or "none".
2. Set closest to the animal, other than the cat, that shares the most ranks with the cat.
3. Set only_kingdom to the animals that share only the kingdom with the cat.