Why dose not give you option to use e-mail like before? it always takes me to the go'o'gle mail option.

Mucous membranes.. a. cover or line external surface of body. b. line internal body surfaces that are in contact with the environment. c. produce antibodies to combat infection. d. secrete sweat, which has antibacterial enzymes.

True or false. mucous membranes secrete mucus that traps pathogens.

If you are having a hard time lifting something, you should arch your back. a. true b. false