The correct option is C.
if two organisms are in the same class then they will be in the same phylum. The biological classification hierarchy is arranged in such a way that, two organisms who belong to a lower division on the hierarchy will automatically be in the same group in the higher division.
The arrangement from the smallest to largest hierarchy is this: specie, genus, family, order, class, phylum and kingdom.
Answer:
C. the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing.
Explanation:
The central chemoreceptors are located near the medulla inside the blood-brain barrier. When CO2 in cerebrospinal fluid increases, pH of the fluid lower (because CO2 becomes hydrated to carbonic acid). Change in pH stimulates the central chemoreceptors to activate respiratory centers which will increase the respiratory rate and depth of breathing.