**Core Concept**
The functional matrix theory proposes that the growth and development of skeletal tissues are influenced by the mechanical forces exerted on them, rather than solely by genetic or hormonal factors. This concept is essential in understanding the adaptation of bones to changing loads and the prevention of osteoporosis. The functional matrix theory is a key concept in bone physiology and biomechanics.

**Why the Correct Answer is Right**
The correct answer is based on the idea that the mechanical environment plays a crucial role in regulating bone growth and remodeling. When bones are subjected to mechanical loads, such as weight-bearing activities, they respond by increasing bone density and strength. This is achieved through the activation of osteoblasts, which produce new bone matrix, and the inhibition of osteoclasts, which resorb bone. The functional matrix theory suggests that the determinant growth of skeletal tissues resides in the mechanical forces exerted on them, rather than in genetic or hormonal factors.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately reflect the functional matrix theory. While genetics and hormones do play a role in bone growth and development, they are not the primary determinants of skeletal tissue growth.
**Option B:** This option is incorrect because it is too broad and does not specifically address the mechanical forces that drive bone growth. While muscle and nervous system function are important for overall health, they are not directly responsible for the growth and development of skeletal tissues.
**Option C:** This option is incorrect because it is not supported by scientific evidence. The functional matrix theory specifically suggests that mechanical forces, rather than genetic or hormonal factors, drive the growth and development of skeletal tissues.

**Clinical Pearl / High-Yield Fact**
One important clinical application of the functional matrix theory is the prevention of osteoporosis through weight-bearing exercise and mechanical loading. Regular weight-bearing activities, such as walking or running, can help to maintain bone density and strength, reducing the risk of osteoporotic fractures.

**Correct Answer:** C.