Final answer:
The first line of defense includes the skin, mucous membranes, and stomach acidity, acting as mechanical, chemical, and biological barriers to prevent pathogen entry and colonization.
Step-by-step explanation:
Ways in Which First Line Defenses Protect Our Bodies
The first line of defense in our bodies is crucial for preventing microbial invasion. Among the options provided, 'C) Skin integrity, mucous membrane, stomach acidity' accurately describes three ways in which these defenses protect us. Firstly, skin integrity acts as a physical barrier, preventing pathogens from entering the body. Secondly, the mucous membranes trap microbes and help expel them from the body. Lastly, stomach acidity is a chemical barrier that destroys pathogens.
The first line of defense comprises mechanical barriers such as the skin and mucous membranes. Chemical barriers include enzymes and acids that destroy pathogens upon contact. Finally, biological barriers take the form of harmless bacteria that compete with pathogenic bacteria, preventing their colonization in our bodies.