## Core Concept
The functional matrix theory, revisited by Moss, pertains to the growth and development of the craniofacial complex. This theory emphasizes the interplay between the functional demands placed on the craniofacial structures and their subsequent growth and adaptation. It involves various biological and biomechanical factors.

## Why the Correct Answer is Right
Moss's functional matrix hypothesis suggests that the growth of the bone is a response to the demands placed upon it by the soft tissues. The key components include:
- **Bone as a substrate**: Providing structural support.
- **The functional matrix**: Comprising muscles, tendons, and other soft tissues that dictate the functional demands on the bone.
- **Epigenetic factors**: Influencing growth through external environmental factors.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is not specified, but if it aligns with one of the known aspects of Moss's theory, such as bone, cartilage, or the soft tissue matrix, then it would be correct and not the answer we're looking for.
- **Option B:** Similarly, without specifics, if this option matches another aspect of the theory, it would be incorrect as an "except" answer.
- **Option D:** Likewise, if this option fits within Moss's theory components, it would not be the correct answer to the "except" question.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the functional matrix theory underscores the importance of soft tissues in guiding craniofacial growth. This concept is crucial in understanding various craniofacial anomalies and in planning their treatment. For example, in conditions like Pierre Robin sequence, understanding the interplay between the tongue, airway, and mandibular growth is vital for management.

## Correct Answer: D.