Unit Four 4a 1. impressed, 2. distributed, 3. analogy, 4. energy, 5. perpendicular, 6. speculate, 7. text, 8. administer, 9. rejected, 10. spontaneous, 11. assembled, 12. intervene 4b 1. sphere, 2. psychology, 3. investigate, 4. axis, 5. appraises, 6. symbols, 7. heredity, 8. discourse, 9. acquire, 10. tentative, 11. emotion 4c 1. d, 2. k, 3. e, 4. a, 5. l, 6. j, 7. f, 8..