The age of a tree can be known by examining A. Cambium layer B. Annular rings C. Medullary rays D. Heart wood

The correct answer is B. Annular rings.

Annular rings are the annual growth rings in a tree trunk. They are formed by the cambium, a layer of cells between the bark and the wood. The

The width of each annular ring is determined by the amount of growth that occurred in that year. In years with good growing conditions, the rings will be wide. In years with poor growing conditions, the rings will be narrow.

By counting the annular rings, it is possible to determine the age of a tree. This is a common method used by foresters and arborists.

The other options are incorrect.

• The cambium layer is a thin layer of cells that produces new cells on the inside and outside of the tree. It is not visible from the outside of the tree.
• Medullary rays are thin, vertical bands of cells that transport water and nutrients from the roots to the leaves. They are not visible from the outside of the tree.
• Heart wood is the inner part of the tree trunk. It is dark in color and does not contain living cells. It is not used to determine the age of a tree.