Which material is primarily made of wood strands bonded with adhesives to form panels with directional properties?

Oriented Strand Board (OSB) is composed of wood strands that are bonded together using adhesives, allowing for a product that has specific directional properties in terms of strength and performance. The strands are arranged in layers, with the outer layers oriented in the same direction to enhance the structural integrity and load-bearing characteristics, while the inner strands may be oriented in different directions. This process contributes to its durability and makes it ideal for various applications in roofing and construction where strength and stability are crucial.

In contrast, the other materials listed have different compositions and structures. Medium Density Fiberboard (MDF) is made from wood fibers that are broken down, combined with adhesives, and formed into sheets, resulting in a denser and smoother product but lacking the directional strength of OSB. Plywood is manufactured by layering thin sheets of wood (veneers) that are glued together, providing strength through cross-lamination rather than through the use of strands. Particle Board is created from smaller wood particles that are bonded together with adhesives but does not have the same structural properties or load-bearing capability as OSB. Hence, OSB stands out as specifically made of wood strands with directional bonding properties, which is why it is the correct choice.