Explain why learning word meanings is difficult
for toddlers.

Which of the following statements regarding emotion and altruism is true

Articular cartilage to shocks and prevents friction between parts.

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.