What is common in the construction of plywood in terms of wood grain orientation?

In the construction of plywood, the correct answer emphasizes that the grains typically run perpendicular across layers. This specific arrangement is integral to the strength and durability of plywood. Each layer, known as a veneer, is glued together with the grain of one layer oriented at a right angle to the grains of the adjacent layers.

This perpendicular orientation helps to balance the expansion and contraction of the wood, minimizes warping, and increases the overall structural integrity of the plywood. As a result, plywood can withstand various stresses better than solid wood and offers enhanced stability, making it a preferred material in construction and furniture making.

The other options do not accurately describe how plywood is constructed. Grains in parallel layers or aligned to create patterns would not provide the same stability and strength, while random arrangements could lead to weak points in the material, undermining the key benefits of plywood.