What Is an Anxiety? Anxiety is a natural human reaction that involves the mind and body. It serves an im po rtan t basic survival function : anxiety is an alarm system that IS activated whenever a person perceives danger or threat. When the body and mind react to danger or threat, a person feels physical sensations of anxiet y — things like a faster heartbeat and breathing, tense muscles, sweaty palms, a queasy stomach. and trembling hands or legs. These sensations are part of the body's fight-flight response (逃避反应) . They are caused by a rush of adrenaline( 肾上腺素 ) and other chemicals that prepare the body to make a quick getaway from danger. They can be mild or extreme. The fight-flight response happens instantly when a person senses a threat. It takes few seconds longer for the thinking part of the brain (the cortex) to process the situation am evaluate whether the threat is real , and if so, how to handle it. If the cortex ( 皮层) sends the all-clea r signal , the fight-flight response is deactivated and the nervous system c an relax. If the mind reasons that a threat might last, feelings of anxiety might linger, keeping the person alert. Physical sensations such as rapid, shallow breathing ; a pounding he art ; tense muscles;and sweaty palms might continue,too. 答案中 R:Right对; W: wrong;错 N: Not mentioned 没提到