Final answer:
Air is the poorest conductor of heat among the options listed because materials like Styrofoam and goose-down feathers use air's poor thermal conductivity to provide insulation.
Step-by-step explanation:
The student asked which tangible material is the poorest conductor of heat. Among the options given, air is recognized as the poorest conductor of heat. This is because materials like Styrofoam, fiberglass, wool, and goose-down feathers are good insulators precisely because they incorporate small pockets of air, utilizing air's poor thermal conductivity to their advantage.
The poorest conductor of heat among the given options is d. Styrofoam. Styrofoam is an excellent insulator because it incorporates many small pockets of air, which has poor thermal conductivity. Other good insulators include fiberglass, wool, and goose-down feathers.
Therefore, while other materials listed such as Styrofoam and LI-900 Silica are also poor conductors of heat, air itself, which is a component of these insulating materials, is the poorest conductor among the options.