Explanation:

 If the stressful external conditions are localised or remain only for a short duration, the organism has two other alternatives.

Suspend: In bacteria, fungi and lower plants, various kinds of thick-walled spores are formed which help them to survive unfavourable conditions – these germinate on the availability of a suitable environment.

In higher plants, seeds and some other vegetative reproductive structures serve as means to tide over periods of stress besides helping in dispersal – they germinate to form new plants under favourable moisture and temperature conditions. They do so by reducing their metabolic activity and going into a date of ‘dormancy’. In animals, the organism, if unable to migrate, might avoid the stress by escaping in time.

The familiar case of Polar Bears going into hibernation during winter is an example of escape in time. Hence, pair 1 is correctly matched.

Hibernation is when an animal slows its heart rate to save energy and survive the winter without eating much. Some animals just slow down and move less frequently during hibernation, but others go into a deep sleep and don't wake up till spring.

Some snails and fish go into aestivation to avoid summer–related problems-heat and desiccation. Hence, pair 2 is not correctly matched.

Aestivation is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a lowered metabolic rate, that is entered in response to high temperatures and arid conditions. It takes place during times of heat and dryness, the hot dry season, which are often the summer months.

Under unfavourable conditions, many zooplankton species in lakes and ponds are known to enter diapause, a stage of suspended development. Hence, pair 3 is not correctly matched.

Diapause is a phase of dormancy in insects and zooplankton. Insects can undergo diapause during the summer or winter as eggs, larvae, pupae, or adults and may be used as a predator avoidance mechanism.