There are two graphs as shown in the figure of the velocity-time graph. The one similarity between the two graphs is that both show uniform ____.

There are two graphs as shown in the figure of the velocity-time graph. The one similarity between the two graphs is that both show uniform acceleration.
 As it is a velocity-time graph and therefore, a straight line in a velocity-time graph represents that the motion of the body is uniformly accelerated; both the graph showing uniformly accelerated motion and also in the first graph, the initial velocity is zero, but in the second graph the body already has some velocity.