When looking at growth in a human embryo, the head develops before the rest of the body. such growth from the head to the base of the spine illustrates the principle.

Cephalocaudal.

Explanation:

Cephalocaudal refers to the head to the toe of the body. The cephalocaudal principle denotes the motor and the physical development of the individual infants to the early childhood.

This principle explains the phenomena of the post natal development  and includes the development of the weight, size, and differentiation of the body. The development always occur from the top to the bottom fashion. The first control of the head will occur and later the toe.

Thus, the answer is cephalocaudal.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.

this is more of a statement than a question. is there answers to go along with this, or is it opinion based?