The correct answer is option 4: Regulate body temperature. Perspiration, also known as sweating, is an essential bodily function that helps regulate body temperature. When we engage in physical activity or are in a hot environment, our body temperature rises. To cool down, sweat glands in our skin produce sweat, which then evaporates from the surface of our skin. This evaporation process helps dissipate heat and bring our body temperature back to a normal range. Perspiration also helps eliminate some waste products and toxins from our body, but its primary function is to regulate temperature. It is important to note that perspiration itself does not eliminate body odors; rather, it is the interaction between sweat and bacteria on our skin that can lead to odors.