Answer :

To determine the maximum percentage of original tissue strength a healed scar will reach by 2 years after injury, let's consider the given maximum strength value:

1. Understanding the context: When a wound heals, scar tissue forms. Scar tissue is the body's way of repairing damage, but it's not as robust as the original tissue.
2. Timeframe: We are given a period of 2 years post-injury.
3. Maximum strength: We are asked for the maximum strength that the scar tissue can achieve compared to the original tissue.

It is established that after 2 years, the maximum strength the scar tissue can reach is 80% of the original tissue's strength.

Thus, a scar will reach a maximum of 80% of original tissue strength by 2 years after injury.