sentence2_structure: A(n) organ<>is<>a structure that is composed of one or more types of tissues$$$a structure<>is composed<>of one or more types of tissues
sentence1: Histology involves both the examination of the characteristics of the four basic tissue types and the structure and organization of organs and organ systems.
sentence2: A(n) organ is a structure that is composed of one or more types of tissues.
question: What is a structure that is composed of one or more types of tissues?