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.
Answer:
The part of your nervous system that is similar to the autopilot of the airplane is the autonomic nervous system
Explanation:
The autonomic nervous system is regulated by the hypothalamus which in turn controls functions such as digestion, urination and other unconscious functions.
I think the answer is C) Knots are related to the global coordinate system.
A) a common ancestor
Homologous structures are structures that are similar in related organisms. There is a basic pattern of bones which can be inherited from a common ancestor
