4. which immune cells circulate in the body, providing immunity by producing antibodies?

Antibodies are produced by white blood cells called B cells ( B lymphocytes ) and they develop from stem cells in the bone marrow. B cells are activated when an antigen is present.

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: