Surface area to volume ratio governs diffusion time in agar blocks

Steps:

• Calculate radius: Block 1 r = 12/2 = 6 mm; Block 2 r = 16/2 = 8 mm; Block 3 r = diameter/2 (unreadable).
• Compute SA using 2πrh + 2πr² and V = πr²h for Blocks 1 and 2: Block 1 SA/V = (2/6 + 2/3) = 1 mm⁻¹; Block 2 SA/V = (2/8 + 2/6) ≈ 0.58 mm⁻¹.
• For Block 3, diameter unreadable prevents SA/V calculation; times cannot be verified without it.
• Match choices to calculated SA/V and inverse relation (higher SA/V, shorter time), but incomplete data blocks full verification.

Not enough information.

Why C is correct:

• Not enough information to confirm, but assumes matching observed times if diameter readable.

Why the others are wrong:

• A: SA/V values inconsistent with formula (e.g., Block 1 not 0.75).
• B: SA/V values wrong (e.g., Block 1 not 0.35, contradicts higher for smaller block).

Final answer: Not enough information.