In of an essay, the writer can summarize all the connections that were made between ideas and evidence throughout the essay.

body
conclusion
introduction
rebuttal

CONCLUSION

Definitely, the definition which you attached above should look like this by using the second following option  :

In the conclusion of an essay, the writer can summarize all the connections that were made between ideas and evidence throughout the essay.

Because body of an essay is actually fully organized text with its main idea and supporting sentence. In other words - your whole text.
Introduction obviously cannot summarize essay's points because it is used to make a start. 
And rebuttal is used for disproving some points from the essay.