Question

the text states that mucous membranes are a key part of the first line of defense. how do they exemplify both a mechanical and a chemical barrier? they have cilia that are acidic and tough skin cells that contain enzymes. they are living organisms that compete with pathogens and also block them physically. they flush out pathogens with urine and also kill them with stomach acid. they secrete mucus that physically traps pathogens, and this mucus contains enzymes that destroy them. a classmate claims, the first line of defense is more effective against bacteria than viruses because viruses are not alive. evaluate this statement based on the information provided. the statement is correct because chemical barriers like enzymes can only target living cells. the statement is correct because viruses are too small to be trapped by mechanical barriers like mucus. the statement is incorrect because the first line of defense is non - specific and works to block all types of pathogens. the statement is incorrect because viruses are actually a type of protozoa, which are easily blocked by the skin

Explanation:

For the first question, mucous membranes secrete mucus which is a physical (mechanical) trap for pathogens and the mucus contains enzymes (chemical) that destroy them. For the second question, the first - line of defense in the immune system is non - specific and aims to block all types of pathogens, including viruses and bacteria.

Answer:

1. They secrete mucus that physically traps pathogens, and this mucus contains enzymes that destroy them.
2. The statement is incorrect because the first line of defense is non - specific and works to block all types of pathogens.