What does X represent in the diagram? (A) The heart (B) The brain (C) A thermoreceptor in the skin (D) A pressure receptor in a blood vessel - HSC - SSCE Biology - Question 7 - 2015 - Paper 1

To determine what X represents, we need to analyze the function of the structures mentioned in the options provided.

• The heart: Typically associated with circulation and does not represent a sensory function.
• The brain: Central processing unit for bodily functions, including sensations but does not represent a receptor directly.
• A thermoreceptor in the skin: This specifically detects temperature changes, which would be visible in a diagram related to skin sensation.
• A pressure receptor in a blood vessel: This detects blood pressure and is a common feature of diagrams showing cardiovascular or homeostatic functions.

Given that X likely represents a structure indicative of sensory functions depicted in the diagram settings, the correct answer is (B) The brain.