7. The loudness of a person’s voice depends on the ________.        

43. Which is the correct symbol for deoxyhemoglobin?

38. This is a common disorder characterized by the temporary cessation of breathing during sleep.

12. Which of the following is NOT a stimulus for breathing?  

4. Tracheal obstruction is life-threatening.

41. The placenta, a vitally important metabolic organ, is made up of a contribution from mother and fetus. Which portion is from the fetus?        

37. The result of polyspermy in humans is ________.        

34. A pregnant woman urinates more often than usual because the uterus compresses the bladder, her metabolic rate and blood volume are increased, and she must also dispose of fetal metabolic wastes.

21. Erection of the penis results from ________.        

10. The dartos and cremaster muscles are important to the integrity of the male reproductive system. Which of the following best describes the role they play?