Final answer:
Defects in engineering units that can result in failure or reduced usability include material defects, design flaws, and manufacturing errors.
Step-by-step explanation:
In the context of an engineering unit, there are several defects that could result in failure or significantly reduce its usability for its intended purpose.
Material defects such as cracks, voids, or inclusions can weaken the unit and lead to structural failure.
Design flaws that overlook essential features or miscalculate stress levels can also result in failure. For example, a poorly designed bridge may not be able to support the intended load.
Manufacturing errors such as incorrect dimensions, improper assembly, or inadequate quality control can introduce defects and compromise the unit's functionality.