Final answer:
The most commonly affected tonsils by tonsillitis are the palatine tonsils located on each side of the throat.
Step-by-step explanation:
The most commonly affected tonsils by tonsillitis are the palatine tonsils. These tonsils are located on each side of the throat in the area of the fauces, which is the opening between the oral cavity and the oropharynx. Tonsillitis is an inflammation of the tonsils usually caused by bacterial or viral infections.