Which two substances work together to maintain skin moisture balance?

The substances that work together to maintain skin moisture balance are sweat and sebum. Sebum is an oily substance produced by the sebaceous glands in the skin, which helps to form a barrier that prevents water loss. This oily layer plays a crucial role in keeping the skin hydrated.

On the other hand, sweat is produced by sweat glands primarily to regulate body temperature, but it also provides moisture to the skin's surface. When combined, sebum and sweat maintain the skin’s optimal moisture levels, creating a protective layer that keeps the skin hydrated and prevents it from becoming dry or cracked.

The other options contain substances that may contribute to skin health or appearance but do not primarily function together specifically to maintain moisture balance in the same effective way as sweat and sebum do.