The object represented by the graph is not in motion at a) 1 second

It's possible, but not definite, that the object is not in motion in the time interval from 5 seconds to 10 seconds.

This is a graph of displacement, not distance traveled. So if the object were, let's say, revolving around the starting point at a distance of 9 meters, from 5 to 10 seconds, it would produce the same graph.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.