sentences:  Therefore, when planning new exhibits today this is taken into consideration.Within the twentieth century great strides had been made in the development of management methods and of principles and techniques relating to the maintenance of captive populations that increasingly satisfied the physical and psychological needs of the animals.Together with the increasing practical experiences in modern animal husbandry, various developments in the science of veterinary medicine (in particular prevention and control of parasites and causes of disease), enormous technical advances and the accumulation of knowledge of all kinds, it became possible to venture exhibits which before had not seemed possible.