The practice of was an early approach to explaining the functions of the brain that involves analyzing the pattern of bumps on a person's skull.

The answer in the space provided is phrenology. This is an approach of studying the skull of a human that will contribute into studying the person’s mental abilities with the use of the size and shape the skull has provided.

Phrenology

The practice of phrenology was an early approach to explaining the functions of the brain that involves analyzing the pattern of bumps on a person's skull.

Phrenology is a scientific concept that explains how the shape of a person’s skull is associated with his character. This concept was started by the anatomist Franz Joseph Gall in the early 1790s. Phrenology involves examining the structure or pattern of unevenness (bumps) on an individual’s skull to determine intellectual aptitudes and character traits of the person. In the mid-19th century, phrenology was discredited and its practice was later stopped.

the answer is:

carbon dioxide