Answer:
In antecedent drainage, a river cuts through a mountain range that is being uplifted by tectonic forces. The rate of down cutting of the river is influenced by the rate of tectonic uplift.
If the rate of tectonic uplift is slow, the river will be able to keep pace with the uplift and maintain its course. In this scenario, the rate of down cutting will be relatively slow.
If the rate of tectonic uplift is fast, the river may not be able to keep pace with the uplift and will be forced to cut down into the rising mountain range. In this scenario, the rate of down cutting will be relatively fast.
Therefore, the rate of down cutting is directly related to the rate of tectonic uplift in antecedent drainage.