1. E. Endorphins 2. B. Diabetes (Friday Special) 3. B. Nitric oxide (NO) 4. D. Two recessive color blindness alleles on the X chromosomes 5. A. Pleiotropy 6. A. True 7. C. Carbon dioxide levels in the blood rise to high levels 8. D. LDL's 9. C. Reduced exposure to sunlight by small children (Friday Special) 10. A. Kidney stones 11. B. Oligodendrocytes (Friday Special) 12. C. Water conservation 13. A. Release drugs 14. D. Variable environments 15. C. Angioplasty 16. C. Hypothalamus 17. C. Females are ornamented, males are choosy, and males carry eggs in a brood pouch until hatching 18. B. Intermediate relatedness (third cousins) resulted in the highest reproductive success 19. E. Creating faceless avatars of actual male dancers which females then rated 20. B. The coefficient of inbreeding 21. A. Formaldehyde 22. B. Recessive alleles 23. E. Antiseptic environments that alter the immune system (Friday Special) 24. C. Surfactant (Friday Special) 25. C. Helicobacter pylori 26. B. Urea 27. B. Water (Friday Special) 28. B. 100% or E. 50% 29. B. Tuberous sclerosis 30. D. Crossing over of the SRY gene (Friday Special) 31. D. Malaria 32. B. Atrioventricular valves 33. B. A multiple allele system 34. C. 1 in 2 35. C. Inbreeding depression 36. E. Anterior pituitary 37. C. Modifier genes affect the expression of the tongue-rolling allele 38. A. Acetylcholine 39. D. Homogametic 40. A. The production of germ cells with half the number of chromosomes found in the parental cells 41. C. Activation of genes 42. C. The placebo effect (Friday Special) 43. B. Melatonin 44. A. Pheromone 45. D. Ectothermic homeotherms 46. E. Releasing hormones 47. A. Serotonin 48. E. Dopamine 49. B. Ammonia 50. A. Prostaglandins