Which part of the immune system is a physical barrier?

skin
tears
mucus
stomach acid

The skin, mucous membranes, and endothelial throughout the body serve as physical barriers that prevent microbes from reaching potential sites of infection.

Skin is the right answer

Explanation:

the skin is the outermost layer that acts as a barrier to bacteria

explanation:

daily refers to frequency, like weekly or monthly. take this medicine twice daily, once in the morning and again at bedtime. on a daily basis there refers to everyday life, to one's normal or usual behavior, activity, routine, or schedule, to the quotidien.

answer188 to 210 calories;