Name one physical and one chemical barrier that protects your body from pathogens and explain how it works.

Ava has an important exam coming up for which she feels unprepared. what is the best way for ava to relieve her stress about the exam? question 17 options: indulge in a little more coffee than usual to increase her concentration on the day of the exam. limit her time spent thinking about the exam and focus on leisure activities. spend extra time relaxing, sleeping, and watching television in the days leading up to the exam. manage her time by setting up a study schedule for the week prior to the exam.