25. In mammals, blood returning from the head will pass through the ________ just before entering the right atrium.
(A) left atrium
(B) superior vena cava
(C) inferior vena cava
(D) aorta
(E) right atrium

21. Which hormone is produced by adipose cells and helps to control appetite? (A) insulin (B) bile (C) gastrin (D) leptin (E) interferon

22. Which statement regarding breathing and circulation in insects is false? (A) Insects lose very little water by using a tracheal system to breathe. (B) The tracheal system of insects consists of a series of branching air tubes that extend from the surface to deep inside the body. (C) Terrestrial animals such as insects spend much more energy than aquatic animals to ventilate their respiratory surfaces. (D) The circulatory system of insects is not involved in transporting gases. (E) Insects spend little water by using a tracheal system to breathe.

23. What part of the human brain contains control centers that establish a breathing rhythm? (A) midbrain (B) cerebellum (C) pituitary (D) thalamus (E) medulla oblongata

複選題24. Which statement about mammalian circulatory systems is false? (A) The pulmonary circuit carries blood between the heart and the lungs. (B) The systemic circuit carries blood between the heart and the rest of the body. (C) Mammals have two atria and two ventricles in their hearts. (D) The left side of a mammal's heart sends blood to the lungs. (E) The pulmonary circuit carries blood between the heart and the body.

26. During ventricular systole, the semilunar valves ________ and the AV valves ________. (A) open； open (B) close； open (C) open； close (D) close； close (E) open, unchanged.

27. Which of the following cells are phagocytes? (A) monocytes and neutrophils (B) basophils and eosinophils (C) eosinophils and lymphocytes (D) lymphocytes and basophils (E) monocytes and mast cells

28. Which is the correct order of steps taken by B and T cells to defend against infection in body fluids and cells? 1. B and T cells move to the lymph nodes, spleen, and other parts of the lymphatic system. 2. B and T cells leave the bone marrow and thymus and move to the bloodstream. 3. B and T cells meet and begin to fight viruses or other infectious agents. 4. B and T cells develop antigen receptors.(A) 4, 2, 3, 1 (B) 2, 4, 3, 1 (C) 4, 3, 2, 1 (D) 2, 4, 1, 3 (E) 4, 2, 1, 3

29. Clonal selection (A) determines the pool of mature leukocytes that will be stimulated by macrophages. (B) requires the activation of natural killer cells. (C) describes the proliferation of B and T lymphocytes after they have been activated by an antigen. (D) requires the presence and activation of complement. (E) describes the selection of mature non-self T cells.

30. Complement proteins can do all of these functions except (A) enhance phagocytosis by innate immune cells by attaching to cell invaders. (B) help trigger the inflammatory response. (C) attack cancer and virus-infected cells after they are released by natural killer cells. (D) act as chemical signals to recruit more immune cells to the site of infection. (E) lysis of target cells.

31. What is passive immunity dependent upon? (A) a person's own immune system producing antibodies (B) antibodies made by another organism (C) antibody-producing cells from another organism (D) antigens from a person's own body (E) antigen stimulates antibody production