At what age do babies have increased levels of digestive enzymes, making it suitable to introduce solid foods? question 8 options: six to eight months three to six months two to three months four to six months

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.