Question

Use the drop-down menus to determine whether the following barriers are physical, chemical, or biological. lysozyme skin phagocytes Langerhans cells acid and oil secretions sneezing or coughing

Answer 1

Lysozyme - Chemical barrier;
Lysozyme is a substance found in saliva, tears, and mucus that destroys the cell wall of bacteria
Skin- physical barrier
The skin has closely packed cells and it is  tough, flexible and also water proof. 
Phagocytes -Biological barriers;
They are types of white blood cells that help protect against pathogens. 
Langerhans cells- Biological barriers;
These are specialized cells in the skin that identify pathogens that enter the body and carry them to the lymph nodes for destruction. 
Acid and Oil (skin secretions) - Chemical barriers;
These are secretions from the skin that help to keep microorganism from entering the body
Sneezing and coughing - Physical barriers.
Type of reflexes that helps keep microbes and pathogens from gaining access to the body systems. 

Answer 2

Ans.

Different barriers present in the body prevent entry of disease causing agents or pathogens from entering into body and provide protection against them. These barriers include various physical, chemical, and biological barriers.

Physical barrier include skin and coughing and sneezing. Skin provides first line of defense by preventing entry of pathogens, and coughing and sneezing that expels harmful agents out of the body.  

Chemical barriers include lysozyme, acids, and oil secretion. Lysozyme is an enzyme that kills bacteria by targeting their cell wall, while oil and acid prevent microbial growth by providing non-favorable environment for them.

Biological barriers include phagocytes and Langerhans cells. Phagocytes are immune cells that engulf and destroy pathogens and Langerhans cells are antigen-presenting cells that help in elimination of pathogens.