This will be of good assistance
Answer:
Um????????????????? I'm lost
Explanation: so very sorry
Answer:
The body has two lines of natural defense to protect against infection. The first are physical barriers, such as the skin, body secretions and mucous membranes. The second line of defense is the immune system. Specialized immune cells coordinate and execute attacks to kill germs that make it past the body's physical barriers.
Answer:
I determine if the object is a living thing by checking to see if it responds to the environment
