The chemist observed the reaction between the acid and the metal, noting the rapid release of gas bubbles and a rise in temperature.
化学家观察了酸与金属之间的反应，注意到气泡的快速释放和温度的升高。
Which choice best defines “reaction”?
D — Response. “reaction” means response.
Which word means “response”?
A — reaction. “reaction” means response.
reaction — response. In Chinese: 反应，回应.
reaction is pronounced /riˈækʃn/.
The chemist observed the reaction between the acid and the metal, noting the rapid release of gas bubbles and a rise in temperature. (化学家观察了酸与金属之间的反应，注意到气泡的快速释放和温度的升高。)
response, reply, feedback — all close in meaning to reaction (response).
stimulus, cause — each the opposite of reaction (response).
Yes. reaction is on the SAT Prep Basic list — the everyday academic words the SAT assumes you already have. The Digital SAT does not test vocabulary in isolation; words like this one are tested through Words in Context questions, where you choose the word that completes a passage most logically and precisely.
re(back)+action(movement).