Why is the trachea constructed with rings of cartilage

Cartilage rings of trachea have protective role

Explanation:

Trachea is a tube, part of the respiratory system, which allows the passage of the air: from larynx to lungs (primary bronchi). It is enveloped with cartilage rings that prevent collapse of the trachea when there is no air. The cartilage "rings" are C-shaped, except one full ring-shaped - the cricoid cartilage which attaches trachea to the larynx.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.