luke found a box of photos lableled 1970-1995. each photo shows his entire extended family. no dates appear on any od the photos. luke knows his grandmother died in 1985 and his uncle was born in 1975. lukes sister was born in 1990. using this information, how can lucke sort the photos into four batches

Asample of digestive juice was removed from the stomach of a pig. the juice was placed in a test tube along with some grains of wheat. a second test tube was set up containing an equal number of wheat grains, with distilled water rather than digestive juice. the test tubes were kept for 8 hours at 40 degrees c. after 8 hours, the grains inside the digestive juice had broken into tiny particles. the grains of wheat, in the water, were wet but otherwise unchanged. what is the control group?