Answer to Question 1
Radiotherapy is the treatment of disease by the use of x-rays, radium, and other radioactive substances.
Answer to Question 2
C
Explanation: A) Presbyopia is a vision disorder, not movements of the eyes.
B) A stye is a bacterial infection of the eyelid, not movements of the eyes.
C) Correct
D) Conjunctivitis is an inflammation or infection, not movements of the eyes.