Which two hazards are included in in-slab hazards?

The inclusion of electric heating cables and hot water hydronic heating lines as in-slab hazards is correct because these elements are often embedded within the concrete slab of a building and can pose risks during radon mitigation processes. In-slab installations, such as these heating elements, can affect the integrity of the radon mitigation system. If these components are damaged during mitigation work, it can lead to the failure of the heating system or can introduce additional hazards associated with electrical safety and plumbing leaks.

Other potential in-slab hazards typically relate to the infrastructure embedded within slabs that could complicate or hinder radon mitigation efforts, but in this case, focusing on heating systems directly correlates to the construction and mitigation challenges faced by specialists.

The other options include hazards that, while they may pose situations of concern in different contexts (like wildlife or plumbing issues), do not fit specifically within the definition of in-slab hazards that radon mitigation specialists need to prioritize. The emphasis is properly placed on components like electric heating cables which are integral to the slab itself and can substantially impact mitigation strategies and building safety.