There are ______ in the sea.

There are many islands in the sea. In its warm waters there are some little ones. We call them "Coral Islands". A coral island is very nice to look at. It looks like a ring of land with trees, grass, and flowers on it. One part of the ring is open to the water. There is a little round lake inside the island. If you look into this lake, you will see beautiful coral. You may think they are flowers. If you look at a piece of coral, you may see many little holes in it. In each of these holes a very small sea animal has lived. These sea animals make the coral. They began to build under the water. Year after year, the coral grew higher and higher. At last it grew out of me water. Then the sea brought to it small trees and something else. After some years, these things changed into earth. Sometimes the wind brought seeds to this earth. Sometimes birds flew over it and brought seeds to the island. The little seeds grew. In a few years there were plants all over the island. In a few more years there were trees growing there. So you see, these islands were built little by little. The workers were very small. Don’t they teach us a lesson? Can you think what the lesson is?