Final answer:
Many unsoundnesses and blemishes in the bones and muscles can be caused by excessive stress, strain, injury, inherited conditions, or nutritional deficiencies.
Step-by-step explanation:
It is true that many unsoundnesses and blemishes in the bones and muscles are due to various factors such as excessive stress and strain, injury, inherited conditions, or nutritional deficiencies.
These factors can weaken the bones and muscles, making them more prone to damage or abnormalities.