Organs as specialized body structures

Steps:

• Recall that an organ is a distinct part of the body composed of multiple tissue types working together for a specific function.
• Evaluate each option against this definition: check if it's a single structure with varied tissues or something larger/smaller.
• Eliminate options that represent systems (groups of organs), tissues, or cells.
• Confirm the matching option as a classic example of an organ.

Why B is correct:

• The eye is an organ because it consists of multiple tissues (e.g., cornea, retina, lens) that together enable vision, per the biological definition of organs.

Why the others are wrong:

• A: The digestive system is an organ system, a collection of multiple organs like the stomach and intestines.
• C: Blood is a connective tissue, not a solid organ structure.
• D: A neurone is a single cell type in the nervous system, not an organ.

Final answer: B