Which of the following traits is not inheritable? Ability to

Analyze the question: You are asked to find the trait that is not inheritable, meaning it is not controlled by genes passed from parents to offspring.

Concept: Inheritable (genetic) traits are controlled by genes. Common human examples used in WASSCE Biology include:

• Ability to taste PTC (phenylthiocarbamide), controlled by a dominant allele
• Tongue rolling
• Ear wiggling or ear movement
• Earlobe attachment
• Dimples, and others

Step-by-step evaluation:

• A. Taste PTC: Genetic. The taster allele is dominant. Inheritable.
• B. Roll the tongue: Genetic. A classic textbook example of a hereditary trait. Inheritable.
• C. Move the ear: Genetic. The ability to move the ears is a hereditary muscular trait. Inheritable.
• D. "Rool" (roll) the eyeball: Rolling the eyeballs is something nearly everyone can do. It is not a distinct genetic variation that separates people into groups with and without the ability. It is simply a normal voluntary movement of the eye muscles, not a trait that is inherited as a distinct characteristic.

Answer: D. Rolling the eyeball is a normal voluntary action, not a genetically varying trait, so it is the one that is not inheritable.

Tip: For this kind of question, remember the classic hereditary traits that show variation: PTC tasting, tongue rolling, ear wiggling, earlobe attachment, and dimples. If an option is a universal action or something acquired (like a skill, scar, or amputation), it is not inheritable. Also remember that acquired characteristics are not passed to offspring.