OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Which of the following best characterizes a nervous response?

1. Involves gradual changes

2. Is mediated by hormones

3. Is almost instantaneous

4. Involves long-term adaptations

The correct answer is: Is almost instantaneous

A nervous response is best characterized by its almost instantaneous nature. This rapidity is due to the way the nervous system operates, sending electrical impulses along neurons to convey messages quickly between different parts of the body. For instance, reflex actions, such as pulling your hand away from a hot surface, occur within milliseconds due to this immediate transmission of signals through the nervous system. In contrast, responses characterized by gradual changes, hormonal mediation, or long-term adaptations are typical of other systems in the body, such as the endocrine system. Hormonal responses often take longer to manifest because they involve the release of hormones into the bloodstream, which can take time to affect target organs. Long-term adaptations usually pertain to responses that help the body adjust to sustained changes in the environment, such as acclimatization or development, which also occur over a protracted period rather than instantaneously.