Where can organic acids commonly be found?

Organic acids are naturally occurring compounds that are often found in various biological materials. One common source of organic acids is in sebum, which is an oily substance produced by sebaceous glands in the skin. Sebum serves several purposes, including moisturizing and protecting the skin, and it contains fatty acids that are vital for maintaining skin health.

Additionally, organic acids are prevalent in many plants. These acids can play significant roles in plant metabolism, growth, and development. For example, citric acid is found in citrus fruits, and other organic acids contribute to the flavor and preservation of various plant products.

The focus on sebum and plants as sources of organic acids highlights their biological significance in both human physiology and plant ecology, thereby making this option the correct choice in this context.