What part of the nervous system sends signals to the muscles that are voluntarily controlled

What exercise allows you to specify the muscles to be traineda. i sonicb. anaerobicc. isometricd. aerobic

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.

If you feel pain while stretching, you should do any of the following except: a. stretch farther. b. back off the stretch. c. find an alternative. d. stop stretching.