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Hibernation---winter sleep to escape in time e.g., bears. 

Aestivation---summer sleep to avoid heat and desiccation, e.g. snails/fish. 

Diapause---suspended development/activity, e. g. zoo planktons. 

Spore formation---to tide over unfavourable conditions, e.g. fungi/bacteria/lower plants. 

Dormancy---By reducing metabolic activity, e.g. seeds.

Regulators maintain/regulate constant body temperature irrespective of external condition. 

Conformers changing/varying body temperature as per external condition.

Regulators : Humans maintain a constant body temperature of 37°C, in summer when temperature is more outside we sweat, when evaporates causes cooling//in winter when outside temperature much lower than 37°C, we start shivering/ a kind of exercise which produce heat and raises body temperature.

Conformers : In aquatic animals, the osmotic concentration of body fluid changes with that of the ambient water osmotic concentration/external body temperature of reptiles, amphibians, fishes change with that of external temperature.

(a) 'X' axis-Mean annual precipitation (cm) 

'Y' axis Mean annual temperature (0°C)

(b) Grassland - B 

Coniferous forest - E

(c) The mean annual temperature ranges from - 12 to 20°C (error accepted ± 2) and mean annual precipitation ranges from 10 - 125 cm, these are the optimum conditions in tundra biome.

Migration : The organisms (animals) can move away temporarily from stressful habitat to a more hospitable area and return when stressful period is over.

e.g - Humans moving from Delhi to Shimla during summer / many animals or birds undertake long distance migration to hospitable area any one e.g. 

• Spore formation : various kind of thick walled spores are formed which germinate on availability of suitable environment.

e.g -bacteria /fungi / lower plants.

• Dormancy : seeds or vegetative reproductive structures help to tide over stress by reducing their metabolic activity. 

e.g seeds or vegetative reproductive structures of higher plants

• Hibernation : It takes place during winter. 

e.g bears or any other correct relevant example.

Aestivation : It takes place during summer to avoid heat and dessication (in animals). 

e.g snails / fish or any other correct relevant example 

Diapause : under unfavourable conditions zooplanktons enter a stage of suspended metabolic activity. 

e.g zooplankton.

Detailed Answer: 

Three different ways by which organisms overcome their stressful conditions are : 

(i) Migration : Birds like bar-headed geese temporarily move from the stressful environment to the more hospitable environment and may return when the period of stress is over. This phenomenon of moving from one place to another is commonly known as migration. 

(ii) Hibernation (winter sleep) : It is period of long inactivity in which organism reduces all its metabolic activities and undergo a period of long sleep. e.g., polar bear hibernates during winter. 

(iii) Aestivation (Summer Sleep) : It is commonly seen in animals that live in hot and arid conditions. Frogs undergo aestivation. 

Green algae are not found beyond a certain depth in ocean because only about 1 percent of sunlight penetrates at this depth which is not sufficient for the plants to photosynthesize and thus grow, and survive.

Feed on plant parts / plant sap.

Plant sap and other parts of plant.

Species that tolerate narrow range of salinity are called stenohaline species.

Under unfavourable conditions many zooplankton species in lakes and ponds are known to enter diapause, a stage of suspended development.

If one had ever been to any high altitude place (>3,500m like Rohtang Pass near Manali and Mansarovar .in Tibetan Autonomous Region), thepathological effect caused by acute exposure to low partial pressure of oxygen at high altitude is called altitude sickness. Its symptoms include nausea, fatigue and heart palpitations.

Desert plants are not adapted to survive in saline/ aquatic conditions.

Plants are conformers/stenothermal/cannot maintain constant internal environment/temperature/osmotic concentration of the body fluids affects kinetics of enzymes through basal metabolism/activity and other physiological functions of the organisms.

Detailed Answer :

In mangroves the soil is deficient of oxygen because of the presence of excess of water in it. Mangroves plants develop special apogeotropic root called Pneumatophores for respiration as an adaption. Such an adaption is not found in desert plants therefore they are not found in mangroves.

Euryhaline animals Animals which can tolerate a wide range of salinity. Stenohaline animals Animals which can tolerate a narrow range of salinity.

In plants light influences photosynthesis growth and reproduction height influences flower induction, seed germination plant movement etc.

The two types of competitions are

• Interspecific competition
• Intra specific competition In this intra specific competition is more intense because it is an interaction among individuals of same species for similar requirements.