Point count is an appropriate method to monitor a population of swallows while line-transect distance sampling is an appropriate method to monitor a population of tortoises.
Explanation:
Point counts are widely used to count or keep track of birds. An observer can record the birds from a single point for a certain standardized amount of time
While line-transect distance sampling will help in the monitoring of tortoise population. It can show how some individuals are missed and also at the same time establish a method for controlling those number of individuals missed.
The process by which <em>two species evolve</em> as a <em>response</em> to <em>changes in one another over time</em> is called, "coevolution" thus the correct answer is that it is an example of <u><em>COEVOLUTION</em></u>