Final answer:
The term 'unsoundness' often refers to a functional defect in animals that can also be a 'blemish,' which is a visible defect. Choice c) Frequently is the right answer since serious conditions are often visible, thereby being blemishes as well.
Step-by-step explanation:
The question relates to the terms unsoundness and blemish as they pertain to animals, particularly horses. An unsoundness is a more serious issue that usually affects the animal's ability to perform its functions. A blemish, in contrast, is typically a cosmetic issue that does not affect the animal's performance. In response to the student's question, "Often, an unsoundness is also a blemish," the correct choice is c) Frequently. This means that while all unsoundnesses have the potential to be blemishes if they are visible, not all blemishes are unsoundnesses. For instance, a scar from a healed injury might be considered a blemish, while a chronic joint issue is an unsoundness that may also present as a visible blemish.