SQA National 5 Biology Practice Exam

The correct choice is sense organs because these are specialized structures that contain receptor cells specifically designed to detect various types of stimuli such as light, sound, taste, touch, and smell. Each sense organ plays a crucial role in allowing organisms to perceive their environment. For example, the eyes are equipped with photoreceptors that respond to light, while the ears contain hair cells that detect sound waves.

Other options like excretory organs refer to structures involved in the elimination of waste from the body, such as the kidneys and bladder. Essential organs generally denote organs vital for survival but do not specifically relate to the detection of stimuli. Digestive organs are responsible for processing food and obtaining nutrients, which is unrelated to sensory perception. Understanding the distinction among these categories emphasizes the unique function of sense organs in sensory biology.