On a standard Cartesian graph, there are two axes. The Y axis runs vertically, bottom to top and the X axis runs horizontally from left to right.
The x-axis runs horizontally across the graph and the y-axis runs vertically on it.
The one that runs left to right, you mean..
Time is almost always put on the X axis, which runs horizontally. Speed on the other hand, would be shown on the vertical or Y axis.
An oval, or ellipse, has two lines of symmetry. One line runs horizontally through the center, dividing the oval into two equal halves, and the other runs vertically through the center, also bisecting the shape into symmetrical halves. These lines reflect the oval's balanced shape, ensuring that one side mirrors the other across each line. Unlike a circle, which has infinite lines of symmetry, an oval is limited to these two.