Question

strength of plywood is classified by

exposure.

density.

groups, numbers 1 to 5.

veneer grades.

Explanation:

Plywood strength is classified by groups (1 - 5). Group 1 has the highest strength (e.g., Douglas - fir, Larch), Group 5 the lowest (e.g., Western woods like white fir). Exposure relates to durability in weather, density is a property but not classification for strength, and veneer grades relate to appearance.

Answer:

groups, numbers 1 to 5.