Final answer:
The characteristic that describes oily skin is excess sebum production, caused by overactive sebaceous glands. Overproduction of sebum can lead to shiny skin and contribute to acne. Managing oily skin includes regular cleansing to remove excess oil.
Step-by-step explanation:
The characteristic that describes oily skin among the options given is c. excess sebum production. Sebaceous glands, which are located in the dermis of the skin, produce sebum, an oily substance that helps to waterproof and lubricate the skin and hair. People with oily skin tend to have overactive sebaceous glands that produce a higher amount of sebum. This can lead to the skin appearing shiny and may contribute to skin issues like acne. Acne occurs when too much sebum, along with dead skin cells, clogs the pores. This environment can also encourage the growth of bacteria, leading to the development of pimples.
Regular cleansing with mild soap is recommended to help manage oily skin by removing excess oil and dirt, which can help in preventing acne. It's also important to note that sebum has beneficial properties, including waterproofing and antibacterial effects, which are essential for maintaining healthy skin.