Which of the following are functions of the immune system? Select the three correct answers.
A. Bones produce extra white blood cells to increase its defense against
germs.
B. The body filters the blood for waste materials.
C. Cell membrane keeps germs from entering the cell.
D. Lymphocytes create antibodies that attach to the germ.
Read each question and write your answer below.

Describe how the respiratory system exchanges carbon dioxide and oxygen in
the lungs. Include the words carbon dioxide, lungs, trachea and bronchi in
your answer.

K12 unit 8 lesson 8 science