NEET 2011 Biology question

Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?

(1)One can breathe out air totally without oxygen.
(2)One can breathe out air through eustachian tubes by closing both the nose and the mouth.Correct
(3)One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.
(4)The lungs can be made fully empty by forcefully breathing out all air from them

Answer: (2)

Solution

The Eustachian tube connects the middle ear (tympanic cavity) with the pharynx. If the nose and mouth are closed and one forcefully tries to exhale, the air pressure in the pharynx rises and air can be pushed up the Eustachian tubes into the middle ear. This is a possibility for most people, so option (2) is

See the full step-by-step solution

Create a free account to read the complete working, and practise questions like this in a timed test.

Create a free account

Question ID VK-090686