A sixth grade teacher takes students on a field trip to the beach. One student finds several pebbles that have a rounded shape and are smooth to the touch. What process most likely shaped these pebbles? The shape of the pebbles is a result of glacial deposition.

The shape of the pebbles is a result of changes in air pressure.

The shape of the pebbles is a result of weathering and deposition.

The shape of the pebbles is a result of being rolled by ocean water.

The shape of the pebbles is a result of weathering and deposition.

Step-by-step explanation:

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."