| Answer | Crossword Clue |
|---|---|
| REACTIVE | Showing response. |
| reactive | Showing a response to a stimulus |
| reactive | Showing an immune response to a specific antigen |
| aerotropic | showing aerotropism, curvature in response to concentration of oxygen |
| sharpest | Having or showing speed of perception, comprehension, or response |
| thigmotropic | showing thigmotropism, i.e. response to direct contact with a surface |
