Leaves grow all over most plants. Leaves are always some shade of green, although they often have yellow or red patterns on them. Plants use sunlight falling on the green in their leaves, called chlorophyll, to convert air and water into food.
When many coral colonies grow close together over a very long time, they build up to form a reef. Reefs can get so high they come out of the water at low tide, and can be dangerous to ships.
A sheaf is a bundle of a freshly harvested cereal crop like rice or wheat. When harvesting was done by hand, the harvest was bundled up into sheafs that were just big enough for one person to carry.
