Answer:
<u><em>Some cartilage becomes bone through ossification during childhood development. </em></u>
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Explanation:
You forgot to include options.
The pair of characteristics that one must use to classify a fish is the presence of jaw and skeleton type. Agnatha fishes are also called jawless fishes and they lack bony skeletons. Cartilaginous fishes are composed of cartilage skeletons. Bony fishes have bony skeleton structures.
<span>it has a specific activation site for enzyme attachment</span>
<span>Fish have adaptable behaviors and structures so that they can
survive in the wild. These adaptations however differ with regards to context
and environment. Some fishes for example are called stonefish because they can
camouflage in environments that are composed variedly with pebbles and rocks,
and this helps them to avoid predators and thrive. Nevertheless, when these
group of organisms are strayed and become exposed to a new environment they can
be exposed and be vulnerable to predators. </span>
