CBSE Class 12-science Answered

Organisms which cannot migrate tend to overcome adverse environmental conditions by developing several methods. For example, some vertebrates escape the stress caused by unfavourable environmental conditions by escaping in time, like bears go into hibernation during the winters. In angiosperms, seeds and some other vegetative reproductive structures serve as means to tide over periods of stress. They reduce their metabolic activity and go into a dormant state. They germinate to form new plants when favourable conditions return.