Non-functional xylem in the center of a tree trunk is

A. Summerwood

B. Sapwood

C. Heartwood

D. springwood

C. Heartwood

Explanation:

Xylem consists of both sapwood and heartwood. Sapwood is comrpsied of functioning cells whereas heartwood is made up of dead cells. The heartwood is commonly found in old trees. It stores sugar and oils. This is why its color is darker than the sapwood. It acts as a supporting structure for the old trees.