Final answer:
The Cattell-Horn-Carroll theory is a hierarchical model of cognitive abilities with general intelligence at the top, broad abilities in the middle, and narrow abilities at the bottom.
Step-by-step explanation:
The Cattell-Horn-Carroll (CHC) theory is known to be the most comprehensive theory of intelligence. This hierarchical model organizes cognitive abilities in three levels. At the top is general intelligence, followed by a set of broad abilities such as fluid reasoning, short-term memory, and processing speed in the middle. These broad abilities divide further into narrow abilities at the bottom level, which include more specific cognitive skills and are the only abilities that can be directly measured. The structure posits that the narrow abilities are encompassed within the broad abilities, which in turn are integrated under general intelligence.