What types of materials are considered moisture absorbers?

Moisture absorbers are materials that can effectively take in and retain moisture from their surroundings. Wood powder and clays are prime examples of such materials because they have a high surface area and porous structures that allow them to absorb moisture efficiently. Wood powder, for instance, can draw in humidity, making it useful in various applications such as filling in spaces and controlling moisture in different environments. Similarly, clays, particularly those that are hydrophilic, can absorb significant amounts of water, thereby reducing humidity levels and helping to maintain a drier atmosphere.

The other options represent materials that do not possess the inherent properties required for effective moisture absorption. Chemicals that alter embalming fluids may modify the characteristics of the fluid but do not function as moisture absorbers. Plastic and synthetic materials typically repel water due to their non-porous nature, which prevents moisture absorption. Likewise, gelatin and silicone compounds do not serve the purpose of absorbing moisture in the same way that wood powder and clays do, as they may have other functions such as encapsulation or providing a barrier rather than absorbing moisture.