**Core Concept**
The cephalo-caudal gradient of growth refers to the pattern of growth and development in the human body, where growth proceeds from the head (cephalo) towards the tail (caudal) or feet. This principle is essential in understanding the sequence of embryonic development and the growth patterns of various body systems.

**Why the Correct Answer is Right**
The correct answer is based on the concept that growth and development in the human body follow a cephalo-caudal gradient. This means that growth proceeds from the head towards the feet, with the head and neck developing first, followed by the trunk, and finally the limbs. This sequence is due to the influence of various growth factors and hormones that regulate cell proliferation and differentiation during embryonic development. The growth axis, or the direction of growth, is therefore oriented from the head towards the feet.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the cephalo-caudal gradient of growth is characterized by an increase in growth from the head towards the feet, not a decrease.

**Option C:** This option is incorrect because the growth axis is oriented from the head towards the feet, not from the feet towards the head.

**Option D:** This option is incorrect because the cephalo-caudal gradient of growth is characterized by an increase in growth from the head towards the feet, not a decrease from the feet towards the head.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the cephalo-caudal gradient of growth is a fundamental principle in understanding embryonic development and growth patterns in the human body. This concept has significant implications for various medical specialties, including orthopedics, neurology, and pediatrics.

**✓ Correct Answer: B. Increases from head towards feet.**