What is heartwood?
As a tree increases in age and diameter an inner portion of the sapwood becomes inactive and finally ceases to function, as the cells die. The inert or dead portion is called heartwood.

What is sapwood?
Sapwood is a living wood in the growing tree.

Differences between heartwood and sapwood are :-
1. Sapwood is a living part of a tree while heartwood is a non-living part of a tree.
2. Sapwood is not durable when exposed to conditions that promote decay. While heartwood provides structural strength for the tree.

thanxx.. but u miss (b) part.. and got 8 marks....