Light enters the eye through the cornea, the clear, curved layer in front of the iris and pupil. ... By changing its shape, the lens focuses light onto the retina. Through the action of small muscles (called the ciliary muscles), the lens becomes thicker to focus on nearby objects and thinner to focus on distant objects.
        
             
        
        
        
Answer:
The correct answer will be option-nasal cavity.
Explanation:
The pharynx is the hollow tube which is divided into three parts: the nasopharynx, oropharynx, and hypopharynx.
The nasopharynx is the upper part of the throat present behind the nose which is  3 to 4 cm long and 2 to 3 cm wide. The nasopharynx connects the mouth to the nose and allows a person to inhale through the nose.
Thus, the option-nasal cavity is the correct answer.
 
        
                    
             
        
        
        
Cells send out signals when they're in distress.