A noticeable physical appearance of individuals of the same species is called

Step 1: Analyze the question The question asks for the term used for noticeable physical appearance differences among individuals of the same species.

Step 2: Explain the concept Variation means the differences between individuals of the same species. It can be grouped in different ways:

• Morphological variation: differences in the form or structure (outward appearance) of organisms, such as height, skin colour, body size, and shape of the nose or ears.
• Physiological variation: differences in how the body functions, such as blood group, ability to roll the tongue, and tolerance to drugs or diseases.
• Discontinuous variation: distinct categories with no intermediates, such as blood groups (A, B, AB, O) or being male or female.
• Continuous variation: a gradual range of values, such as height and weight.

Step 3: Work through the options

• A. Physical variation: this is not a standard biological term in the classification of variation.
• B. Morphological variation: this refers to differences in outward form and appearance, so it fits the question.
• C. Physiological variation: this concerns body functions, not appearance.
• D. Discontinuous variation: this describes the pattern of variation (distinct categories), not specifically the physical appearance.

Step 4: Answer "Morphological" comes from morph, meaning form or shape, so the term for noticeable differences in physical appearance is morphological variation.

Exam tip: Link the root words to the meaning: morph = form or shape (appearance), physio = function (how the body works). If a question says "appearance, structure, or shape," think morphological. If it says "function, or how the body works," think physiological.