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A. Assertion: Epithelium is well-suited for gas exchange in the lungs. Reason: It consists of multiple layers of tall cells that slow down diffusion.
B. Assertion: Cardiac muscle can contract continuously without fatigue. Reason: Cardiac muscle cells have a high number of mitochondria and an abundant blood supply.
C. Assertion: Tendons connect bone to bone and allow joint movement. Reason: Tendons are made of tough connective tissue that transmits force from muscle to bone.
D. Assertion: In a hinge joint, movement occurs primarily in one plane. Reason: The bone ends are shaped to allow sliding in all directions.
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A → (iv) A is false, R is true... actually the assertion is false (lung epithelium is a single thin layer, not multiple tall layers) and the reason as stated is also false, so the gas-exchange epithelium is thin. Best fit: A is false. The reason describes the wrong structure, so (iv) does not fit perfectly; the assertion is false because lung epithelium is thin and single-layered.
B → (i) Both true and the reason correctly explains it: many mitochondria and a rich blood supply give cardiac muscle the energy and oxygen to work without tiring.
C → (iv) The assertion is false (tendons connect muscle to bone, not bone to bone), but the reason is true (tendons are tough connective tissue that transmits force from muscle to bone).
D → (iii) The assertion is true (a hinge joint moves in one plane), but the reason is false (hinge bones do not slide in all directions).
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