Which of the following can be a physical barrier to prevent termites?

Steel mesh is an effective physical barrier for preventing termites. It serves as a structural safeguard by creating a physical impediment that termites cannot easily penetrate. This material is particularly beneficial because it is durable and resistant to degradation, unlike organic materials, which can attract termites or become compromised over time. When properly installed around the perimeter of a building or in specific vulnerable areas, steel mesh helps to protect the structure from potential termite infestations by blocking their entry points.

In the context of other materials listed, hollowed logs, plastic sheeting, and wooden stakes do not provide the same level of protection. Hollowed logs are organic and can actually serve as a food source for termites. Plastic sheeting, while it may act as a moisture barrier, does not effectively stop termite access on its own and can degrade over time. Wooden stakes are similarly susceptible to termite damage, as they are made of organic material that can easily be consumed by termites. Thus, steel mesh stands out as the most appropriate choice for a physical barrier against termites.