Question

Nasal and oral cavities in the human being is
(a)Diaphragm
(b)Palate
(c)Trachea
(d)None of the above

Answer 1

Hint: Nasal and oral cavity aren't truly separated in animals except for humans and crocodiles. The divider between these two chambers in humans is of two types- one is made of bones whereas the other is made of soft tissues.

Complete answer:
It is the palate that separates the nasal and oral cavities in humans. This is divided into two parts, the hard one is made of two bones of the facial skeleton, and the soft one made of soft tissues. Crocodiles have a similar structure between their oral and nasal cavity but other tetrapods don’t have a separated oral and nasal cavity.

Additional Information: The hard palate is in the roof of the mouth and consists of the two bones- the palatine process of the maxilla and the horizontal plate of the palatine bone. This palate holds the upper teeth and is important for feeding and speech. Om the other hand, soft palate or velum is made of five muscles with their functions are
-Tensor veli palatini (swallowing)
-Palatoglossus (swallowing)
-Palatopharyngeus (breathing)
-Levator veli palatini (swallowing)
-Musculus uvulae (movement of uvula)
Thus, option B is correct.

Note: While the palate is made out of bone and soft tissues, the diaphragm is completely made of muscles and plays an important role in respiration by increasing the capacity of the lungs during inspiration. During this stage, the diaphragm flattens and in expiration, it again goes back to its normal state. It's the divider between chest and abdomen and has functions in breathing as well as help in vomit, urine and feces excretion and prevention of acid reflux.
The trachea is the cartilaginous tube connecting the larynx to the bronchioles. This is very important to carry air from the nose and larynx to the lungs. This has C-shaped cartilaginous ribs that prevent the collapse of the trachea during breathing but make it collapse slightly during eating so that food can pass down to the esophagus while swallowing.