The correct answer is "a well-developed notochord".
Explanation:
The missing options for this question are:
A) paired fins
B) jaws
C) a well-developed notochord
D) a rasping tongue
The correct answer is option C) "a well-developed notochord".
Lampreys and hagfishes are two species of jawless fish that are uncommon to see, but they have more than 30 different species for each one of them. Both lampreys and hagfishes have a well-developed notochord, during their larvae and adult forms. The notochord provides support to their body as it has the function of a cartilaginous skeleton.
