21.17: Chapter 17
( \newcommand{\kernel}{\mathrm{null}\,}\)
Multiple Choice
1. c
3. d
5. b
7. a
9. a
11. b
13. d
15. a
17. c
19. a
21. d
23. c
Fill in the Blank
1. innate / adaptive
3. sickness behaviors
5. fetal yolk sack