The immune systems line of defense against infectious diseases includes the skin

First line of defense.

Explanation: The immune system's way of protection initially begins using the skin to protect against any physical and chemical harm. This is called the first line of defense. Amongst other first line defense mechanism includes; tears to protect from harmful substance in dust and air, cillia inside the nose, the internal mucosal linings to protect against harsh chemicals as well as freindly bacteria called our normal microflora.

the answer to this question is a

image result for describe the various types of gene mutationsghr.nlm.nih.gov

the types of mutations include: missense mutation: this type of mutation is a change in one dna base pair that results in the substitution of one amino acid for another in the protein made by a gene. nonsense mutation: a nonsense mutation is also a change in one dna base pair.

explanation: