Answer: c) and b) are correct.
The brain is encased in a protective bony or cartilaginous housing in craniates.
The anterior end of the nerve cord is elaborated to form a brain in craniates.
Explanation: The craniates include the chordata with well-defined heads. This includes mammals, reptiles and fishes. So we can discard the other answers. Because most craniates have functional jaws, and the adults do not lose their chordate characteristics. The last one does not apply as a specific feature because the tunicate have neural crest but are not recognized as craniata.
Answer:
the increase in size lead to to high ratio hence the large the surface area
The first mutation is substitution and the second is deletion
Sedimentary rocks are formed from pre-existing rocks or pieces of once-living organisms. They form from deposits that accumulate on the Earth's surface.