Final answer:
Cylinders in transit must be fastened to protect against potential accidents or damage.
Step-by-step explanation:
When cylinders are in transit, they must be fastened to protect against potential accidents or damage. If cylinders are not securely fastened, they can become loose and roll around, posing a risk to the safety of the transportation vehicle and its occupants.
For example, if a cylinder is not properly fastened in a truck, it can shift and potentially fall off, endangering other vehicles on the road. Additionally, if a cylinder is not securely fastened on a ship, it can roll and cause damage to the ship's superstructures or cargo.