Final answer:
The inner endoderm layer forms the digestive and respiratory organs, which include parts of the body like the digestive tract and lower respiratory system.
Step-by-step explanation:
The inner endoderm layer forms various parts of the body during development. Specifically, the endoderm is the innermost embryonic germ layer from which most of the digestive system and lower respiratory system derive. Therefore, the correct answer to which structures the inner endoderm layer forms is b. Digestive and respiratory organs.