Chitin is a long-chain polymer derived from glucose. It strengthens cell walls of fungi and the outer covering (exoskeleton) of arthropods (including crabs, shrimps, and insects). The presence of chitin in these groups is likely due to:. A: secondary endoparasitism
B: horizontal gene transfer
C: paraphyletic evolution
D: convergent evolution

Ms. w, a 21-year-old woman, came into a clinic after suffering a deep laceration on her foot while walking barefoot around her yard. the wound was cleaned, sutured, and bandaged, and she was released to return home after receiving tetanus antitoxoid. within 72 hours, the wound area was red and swollen, the suture line was dark in color, and it was accompanied by severe throbbing pain. ms. w had a high fever, her heart felt like it was racing, and she was finding it hard to concentraten even on simple tasks. she returned to the clinic and was immediately taken to the hospital. following lab tests, a diagnosis of acute necrotizing fasciitis was made. discussion questions 1. explain why ms. w. received a tetanus antitoxoid before leaving the hospital. (see chapters 3 and 4, infection and passive immunity.) 2. explain how acute necrotizing fasciitis developed in this case and the pathophysiology involved. (see acute necrotizing fasciitis.) 3. what is the potential outcome for ms. w if antibiotic drugs do not reduce the infection quickly?