Choose the letter of the correct answer, 1. Why is the skeletal system important? A It absorbs nutrients into the blood and to the calls B. It protects the human body skin, C. It provides oxygen for the human body, D. It serves as framework which enables the body to move, 2. Which muscles allow us to consciously move our arms and legs? A, Cardiac muscles B. Involuntary muscles C. Smooth muscles D. Skeletal muscles 3. Which organ serves to filter and warm the air entering in? A. air sacs B bronchus C diaphragm C D. nasal cavity 4. Which of the following is the function of the nails? A Help regulate body temperature, B. Help the body absorb heat from the sun, C Protect fingertips and toes, n Protect the scalp from heat, hin​