Answer: The absolute phrase in the sentence provided is <u>"his chubby legs, pumping"</u>.
Explanation: An absolute phrase is<u> a phrase that is separated from the rest of the sentence by means of a comma</u>. Moreover, absolute phrases only add non-essential information; therefore, if they are eliminated, the meaning of the sentence does not change. Absolute phrases are usually made up of a noun and its modifiers as finite verbs cannot be included. In the sentence provided, <u>"his chubby legs, pumping" is an absolute phrase because it has been set apart from the rest of the sentence by a comma</u> and <u>it is made up of a noun</u> ("legs") <u>and its modifiers</u>. Furthermore, <u>"his chubby legs, pumping" does not include a finite verb</u>.
From the definition of absolute phrases we know that it is a modifier that attaches to a sentence without a conjunctution. So, we can say "his chubby legs, pumping" is the correct answer.