My teacher heaped praise on me for my research project about the civil rights movement
Your answer is praise. In order to select the correct option, you should determine which word category is required in the blank to be filled in. The verb "to heap" means "to direct a great deal of praise, abuse at someone or something". That is why your answer is praise.
"To prey" means "to hunt and kill for food" and "to pray" means "to direct a prayer to God or another deity". Finally, "praize" is the "eye dialect spelling of praise".