Drive 



The complex of internal and external states and stimuli 

 leading to a certain behaviour in an animal. 



Driveway, Stock 



A strip of land set aside for the movement of livestock 

 from one place to another. 



Drosophila 



A genus of flies, order Diptera, much used in research in 

 genetics, e. g. fruit-fly. 



Drought 



An extended period of dryness; usually any period of 

 moisture deficiency that is below normal for a specific area. 



Drought Resistance 



The capability of an organism to survive drought with 

 little or no injury. 



Drumlin 



An oval-shaped hill composed of glacial Drift, usually 

 compact and not stratified, commonly with its longer axis 

 parallel to the movement of the ice when deposition oc- 

 curred. 



Drupe 



A fleshy fruit in which the single seed is within a stony 

 inner cover (endocarp) which is surrounded by a fleshy layer 

 (pericarp), e. g., plum, cherry. 



Drupelet 



A small drupe, e. g., the raspberry fruit is a cluster of 

 drupelets. 



Dry Farming 



(1) Cultivation of land and other farming operations in 

 semi-arid or arid regions without irrigation. (2) A system of 

 cultivation of the land in which Fallow and Mulch are used 

 to absorb and retain much of the precipitation that occurs. 



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