Definition: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Input: How do you know the core of a tree's trunk is likely still intact?, Context: It is remarkable that the inner heartwood of old trees remains as sound as it usually does, since in many cases it is hundreds, and in a few instances thousands, of years old. Every broken limb or root, or deep wound from fire, insects, or falling timber, may afford an entrance for decay, which, once started, may penetrate to all parts of the trunk. The larvae of many insects bore into the trees and their tunnels remain indefinitely as sources of weakness. Whatever advantages, however, that sapwood may have in this connection are due solely to its relative age and position.
Output:
the inner heartwood of old trees remains as sound as it usually does