The contrast in coloration was pivotal to determine if predators attack snakes based on their colors.
It was for studying MIMICRY in snakes.
Assuming all the.snakes were the same the number of attacks will not indicate anything about the effect of the colored rings.
This question on the need for provision of a controlled experiment during experimental investigation. Thus in order to test the effect of a particular condition,another contrasting condition must be provided to determine if the condition under investigation is the actual results obtaned or the influence of other factors in the environment or in the experiment.
The change in the color of the ring is the VARIABLE .In the artificial snake the variable is the presence of this coloed rings against its absence in this snake.
In humans, the flu virus and streptococcal bacteria cause infectious diseases, and they spread from person to person. In contrast, non-infectious (abiotic) disorders in humans include health conditions which are not transmitted from person to person or caused by an infectious agent
