A high blood potassium level (hyperkalaemia)

Correct Answer: C

Rationale: High K+ disrupts cardiac membrane potential, risking arrhythmias; renal failure and crush injuries elevate K+.

Correct Answer: B

Rationale: Cardiac muscles are in the wall of the heart and large veins like pulmonary veins and vena cava. Cardiac muscle fibres have blood vessels so never get fatigued.

Correct Answer: C

Rationale: Epithelial tissues are tightly packed into continuous sheet with small amount of cementing material and no intercellular space.

Correct Answer: B

Rationale: Adipose tissue is specialized for fat storage, providing energy reserves and insulation.

Correct Answer: B

Rationale: Atrophy is the reduction in size or mass of tissues or organs due to cell loss or shrinkage.