Final answer:
The indirect object in the given sentence is 'class,' which answers to whom Alyssa read her story.
Step-by-step explanation:
In the sentence, 'After Alyssa read the class her story about her trip to the beach, she handed her paper to the teacher,' the indirect object is the class. An indirect object receives the direct object and typically answers the question to whom or for whom the action of the verb is done. Alyssa is reading the story to the class, hence the class is the indirect object. The teacher, to whom the paper is handed, is the direct object of the verb 'handed.'