Greg rolled a ball down the street. The ball went 10 meters south in 6 seconds. What was the velocity of the ball?
O A. 1 m/s south
O B. 1.67 m/s south
O C. 0.6 m/s south
OD. 0.2 m/s south

Donald is studying the eating habits of all students attending his school. he samples the population by dividing the students into groups by grade level and randomly selecting a proportionate number of students from each group. he then collects data from the sample. which type of sampling is used? select the correct answer below: systematic sampling convenience sampling stratified sampling cluster sampling