The ear pinna is strengthened by

Step 1: Analyze the question The question asks what gives the ear pinna (the visible, outer part of the ear) its support and shape.

Step 2: Explain the concept The pinna (auricle) collects sound waves and directs them into the ear canal. It must stay firm yet flexible so it can hold its shape and bend without breaking. Two tissues provide support in animals:

• Bone is hard and rigid. It forms the skeleton.
• Cartilage is firm but flexible. It is found in the pinna, the nose tip, and the trachea rings.

Step 3: Evaluate the options

• A. Blood pressure: This moves blood through vessels. It does not give structural support to the pinna.
• B. Cartilage: The pinna is made of elastic cartilage covered by skin. You can bend your ear and it springs back, which shows it is cartilage and not bone.
• C. Bone: Bone is rigid. If the pinna were bone, it could not bend and would break easily.
• D. Turgor pressure: This is water pressure inside plant cells that keeps them firm. It applies to plants, not to the mammalian ear.

Step 4: Answer The ear pinna is strengthened by cartilage, which is option B.

Exam tip: Remember that "flexible support" means cartilage. Bend your ear or the tip of your nose to check: if it bends and springs back, it is cartilage. Also, turgor pressure is a plant-only idea, so eliminate it whenever the question is about animals.