What material is primarily used in the construction of the pallet used for cargo shipment?

The primary material typically used for constructing pallets for cargo shipment is wood, often in the form of plywood or solid boards, instead of specialized materials like aluminum and balsa wood. Wooden pallets are favored due to their versatility, strength, and cost-effectiveness for transporting a wide range of goods. They can support significant weight and withstand the rigors of shipping, including stacking and handling.

While alternatives such as plastic and metal pallets do exist, they are not the most commonly used materials in general cargo shipment. Steel and fiberglass, while they can be strong and durable, are not standard for typical pallet construction due to their weight and cost compared to wooden pallets. Balsa wood, in particular, is too light and fragile for standard cargo shipment needs.

Thus, the most prevalent choice for pallet material remains wood, making the selection of aluminum and balsa wood less applicable in this context.