Adaptations in desert animals -:
Animals excete solid urine and faeces , possess spiny skin and highly cornified skin, they come out during the night or early morning for fedding purposes to prevent loss of water and the scorching heat of the desert.

(b) Adaptations of plants to water scarcity - Plants adapt to water scarcity by having
i. thick waxy coating or cuticle.
ii. sunken stomata
iii. extensive and highly branched root system.
iv. leaves reduced to spines and thick and fleshy stems.
v. By using the Cam pathway for the production of food.

(c) Behavioural adaptations in animals. The various behavioural adaptations in animals are
i. Migration
ii. Hibernation and aestivation.
iii. Certain animals change their feeding and foraging time and pattern.
iv. some animals like lizards(ectotherms) bask in the sun to absorb heat and moving to shade when the ambient temperature increases.

(d) Importance of light to plants-  
Light is the major and ultimate source of energy for plants. Plants use light to synthesize  food. The light also induces photoperiodic responses like it effects flowering in plants. The UV spectrum of the Light is very important for the plants in places where the light cannot reach.

(e) Effect of temperature and waters scarcity and the adaptaions of animals. 

Temperature plays and important role as it affects the kinetics of the enzymes and metabolism, activity and other physiological functions. It also affects the habitat, geographical distribution and pigmentation. The animals of the cold regions develop thick fur and have more fat so as to avoid the cold conditions. The animals which can bear a wide range of temperature have a more distributional range. Certain animals which cannot regulate the temperature for eg. desserts lizards bask in the sun to absorb heat and move to shade when the temperature increases.

Animals tend to adapt to the water scarcity by 
i. Exceting solid urine and faeces ,
ii. Having spiny skin and highly cornified skin, iii. Changing the feeding habits that is they come out during the night or early morning for fedding purposes to prevent loss of water .