Biology - Human Body Systems - Immune system - Three Lines of Defense

Interactive simulation: 'A bacteria is trying to infect you!' Scene 1 - FIRST LINE: 'The bacteria lands on your skin.' Options: 'Skin blocks entry' (correct - skin is a physical barrier) or 'Bacteria walks right in' (wrong). If skin has a cut: 'Bacteria enters through the wound!' Scene 2 - SECOND LI