In a distance vs. time graph, an increasing graph indicates that the distance is consistently growing over time, representing consistent forward movement without any stops or regressions in distance.
If the graph shows one of the animals with a line that slopes upwards throughout the entire duration of the race, that particular animal would be the one exhibiting an increasing graph the entire time.
To give a precise answer, I would need to see the graph itself. However, if the description indicates that one animal's line is always rising, that animal is the one showing an increasing graph throughout the race. Typically, in scenarios like this, the hare or the fox often tends to have a consistently increasing graph if they are faster than the tortoise.