Questions 17 through 21 refer to the following passage: an experiment is designed to determine if wheat grows better when it is planted alone or with clover. the design calls for 3 pans of each treatment. pans a, b, and c contain only wheat. pans d, e, and f contain clover and wheat planted in alternating rows. each pan contains a total of 100 seeds. all treatments contain the same type of soil, are planted in the same size pan, are exposed to the same amount of sunlight, and are maintained at the same temperature throughout the course of the experiment. constants in this experiment are a number of seeds in each pan, sunlight, one pan of wheat and clover. b the pans in which wheat is alternated with clover. c the pan of wheat, temperature, soil type. d temperature, number of seeds in each pan, sunlight. e soil type and sunlight.