Question

What accurately describes physical barriers? i. they are difficult for bacteria and viruses to penetrate. ii. they include the skin and the mucous membranes. iii. they may work in conjunction with secretions like tears and mucus?

Answer 1

All choices correctly describes physical barriers. Physical barriers after composed of tight junctions wherein it is difficult for the bacteria and viruses to penetrate. Examples of these physical barriers are the skin and the mucous membranes and these work in conjunction with secretions like tears and mucus (as tears and mucus contain IgA, a special type of immunoglobulin that is secreted to fight harmful organisms).