The correct answer is B. A bony skeleton
Explanation:
In biology, Chondrichthyes are mainly marine jawed fishes that have cartilage skeletons rather than bone skeletons and also they have paired fins, this includes animals such as rays and sharks. In terms of origin, it is believed this type of fishes are mainly linked to placoderms that were a type of primitive fish that lived during the Devonian period that had a body skeleton as they were covered by hard structures called plates made of bone. Because of this, it is believed this structures evolved into less rigid ones made of cartilage although both the primitive fish and modern Chondrictyles share features such as the structure of jaws. Therefore, Chondrictyles descended from fishes that had a bony skeleton.
D. Would be the correct answer.
some one celled organisms reproduces by binary fission which is a process of cell division. The answer is 4.
Topsoil (horizon A):Very rich in humus(dead organic matter like plants) and minerals.
Subsoil (horizon B):less rich in humus and minerals
Weathered Rock (horizon C):Little or no plant life due to it being all rock
Hope this helps :)
<span>Choanoflagellate.
These are the organisms that are considered to be the single celled protists most closely related to animals because the characteristics that can be found in these organisms are the characteristics that were probably present in the animal's ancestor organism. </span>
