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.
Interactions may be commensalism, mutualism, or parasitism.
Answer:
a. synergism
Explanation:
When two different drugs inhibit a single biochemical pathway of microbes less quantity of each drug is required in combination to produce the effect than when used separately. This effect is called synergistic interaction of drugs.
Both beta-lactam antibiotics such as penicillin and cephalosporin and clavulanic acid serve as beta-lactamase inhibitors and inhibit the beta-lactamase-producing bacteria. Therefore, beta-lactam antibiotics and clavulanic acid are used in combination to control these enteric bacteria.
