Jack and Jill live under a hill and go out everyday to collect nuts and water. Jack can collect a maximum 18 liters of water or 36 ounces of nuts each day. Jill can collect 28 liters of water or 21 ounces of nuts per day. Currently, Jack and Jill each spend half of their collecting nuts and the other half collecting water

1. Calculate the opportunity costs of nuts and water for both Jack and Jill (you will get 4 opportunity costs).
2. Explain who should specialize in collecting which item.
3. If they specialize, how much more water total do they collect compared to when they were each spending half the day collecting water?
4. If they collect 20 liters of water and 26 ounces of nuts, are they producing an efficient combination?