Acolumn of soldiers, marching at 121 steps per minute, keep in step with the beat of a drummer at the head of the column. it is observed that the soldiers in the rear end of the column are striding forward with the left foot when the drummer is advancing with the right. what is the approximate length of the column? (take the speed of sound to be 343 m/s.)

Researchers determine that the biodiversity in a woodland region is declining. they identify two major threats to the region's biodiversity, a method to address each threat, and the expected outcome of each method. this information is shown in the table. a) reforestation would not benefit many species because most forest species live on the ground. b) reforestation would take the longest time to be effective because trees take several years to grow. c) biological augmentation would benefit only a few species because is is typically not very effective. d) biological augmentation would take less time to ve effective because it targets the majority of prey species.