Biology ocr a level exchange surface question

Anyone get this question

23. Organisms can use simple diffusion to exchange gases when the diffusion pathway is less than 1
mm.
A beet armyworm larva:

• has a cylindrical shape
• is 15 mm long
• has a volume of 30 mm3.
Calculate the diffusion pathway of the larva and state whether it could or could not rely on simple diffusion across its external surface to meet its gas exchange requirements