Answer:
<em>The correct option is C) C-shaped cartilage rings </em>
Explanation:
The trachea is commonly known as the wind-pipe. The trachea can be described as about a 4 inch long passage from which the air travels into the bronchi and lungs. The pathway of the trachea is kept open by C- shaped cartilages which are lined all over in the trachea. The C-shaped cartilages protects as well as maintain the shape of the wind-pipe. The rigidity of the trachea arises from the C-shaped cartilages.
B is the incorrect statement, and therefore the correct answer.
The heat conducts and burns
The number indicates the mass number of the atoms of the element. 15N, therefore, is heavier than 14N. Mass number is the total number of protons and neutrons in the nucleus of the atom. While 14N has 7 protons and 7 neutrons, 15N has 7 protons and 8 neutrons.