Which two substances work together to keep the skin moisture balanced?

Sweat and sebum are two natural substances produced by the body that play a crucial role in maintaining skin moisture balance. Sweat, which is produced by sweat glands, helps cool the body and provides hydration to the skin's surface. When sweat evaporates, it can leave behind an emollient layer that helps keep the skin hydrated.

Sebum, on the other hand, is an oily substance secreted by sebaceous glands. It helps to create a protective barrier on the skin's surface, preventing moisture loss and providing a degree of water resistance. Together, sweat and sebum work synergistically to ensure that the skin retains moisture while also protecting against environmental factors that could lead to dryness.

Other options, while they may involve moisture concepts, do not represent the two primary substances that collaborate in this specific physiological function. Water and lotion, for instance, are not naturally occurring substances produced by the body; they are external products used to hydrate the skin. Oil and cream could provide moisture, but they don't function in the same natural way as sweat and sebum. Lastly, sugar and salt do not have a direct role in moisture maintenance of the skin; they are more associated with dietary purposes and can even lead to dehydration when consumed in excess.