1. Why is illegal immigration a controversial issue?
A People think that the current laws on immigration address the issue well.
B There are far fewer illegal immigrants each year than naturalized citizens.
C Americans disagree on whether immigration law should change to address it.
D Most naturalized citizens first entered the United States as illegal immigrants.

the answer is A people think that the current laws on immigration address the issue

- "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."