D hope that helps good day
The first line of defence (or outside defence system) includes physical and chemical barriers that are always ready and prepared to defend the body from infection. These include your skin, tears, mucus, cilia, stomach acid, urine flow, 'friendly' bacteria and white blood cells called neutrophils.
M phase, or mitosis.
(You don't need to know this for your course but more properly cell division could also refer to meiosis or binary fission.)
A more clear understanding of the world around us.
