What type of plastic undergarment covers all parts of the body except the hands?

The correct answer is a unionall. A unionall is a type of garment typically made from plastic or similar materials that extends over the entire body, providing coverage and protection. It is designed to include all body parts except the hands, making it particularly useful in various applications, including those in mortuary science to ensure cleanliness and protection during the embalming process.

In contrast, a coverall generally refers to a similar type of garment but can sometimes imply full-hand coverage, which is not what the question specifies. A body suit is often associated with tight-fitting clothing that may cover the body but does not necessarily align with the specific characteristics of the unionall. A plastic gown may provide coverage but typically is not as comprehensive as a unionall, often leaving more of the body exposed. Thus, the unionall is the most accurate choice based on the description provided.