Yes, it is. When writing an argumentative essay, you are arguing for one side of the topic. For the counterclaim, you want to address the opposing view. In the same sentence, you want to explain why the opposing side is wrong (aka the rebuttal). The format is usually like this:
Though some may believe _______, in actuality (your viewpoint here) is correct because (evidence here).
Usually when writing a counterclaim and rebuttal, it is included at the end of the third paragraph of a five paragraph essay. Make sure you definitely end the third paragraph with a concluding sentence that relates to the topic sentence of that paragraph though.
Answer: The theme of “Taking the Plunge” is to accomplish any challenge you have to overcome your fears on your own. The story tells us that no matter how impossible we think one things is, there is always a way to do it as long as we stay positive and confident. The main character had a problem with her body but that did not stop her from achieving amazing feats that one would think is impossible for her state.