Final answer:
The statement that microbiota act as a biological barrier in areas like the skin, gut, lungs, and nose/oral/eye regions is true. The microbiota consists of beneficial organisms that protect the body by competing for resources with pathogens and altering conditions to inhibit their growth. Barrier actions include skin's normal flora, enzymatic action in saliva, and mucosal layers trapping microbes.
Step-by-step explanation:
The statement that microbiota act as a barrier in the skin, gut, lungs, and areas such as eyes, nose, and oral cavity is true. The microbiota are biological barriers comprising living organisms, primarily bacteria, that help protect the body by occupying space and resources, making it less hospitable for pathogenic organisms to establish and cause infection. They can also secrete substances that make their environment less favourable for harmful bacteria by altering conditions such as pH or releasing inhibitory toxins.
Specific examples of these barrier actions include the skin's dry environment and its own microbiota deterring colonization by transient microbes, saliva in the mouth containing lysozyme—an enzyme that destroys bacteria, and the mucosal layers throughout the body trapping microbes. The gastrointestinal tract, respiratory tract, and other mucus-laden surfaces collaborate in these efforts to prevent pathogens from entering the body and causing illness.
These living biological barriers are part of the body's first line of defence, along with chemical and physical barriers, and function together with cells of the innate immune response, like phagocytes, to fend off invading pathogens.