Gardner's Multiple Intelligences Theory suggests that intelligence is not a single, unified concept but rather made up of multiple intelligences, such as linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal, and naturalistic intelligences.

Spearman's two-factor theory suggests that intelligence is made up of a general factor (g) and specific factors (s), but some critics argue that the theory places too much emphasis on the general factor and neglects the importance of specific abilities.

Gardner's theory of multiple intelligences proposes that there are multiple types of intelligence, including linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, and intrapersonal. This theory emphasizes the importance of specific abilities rather than a general intelligence factor.

The primary characteristic of backward children is their difficulty in learning and understanding new concepts. Other characteristics may include poor academic performance, slow pace of learning, and low levels of motivation.

Mental age is a concept used in intelligence testing to compare an individual's intellectual level to the average intellectual level of individuals at a certain age. This concept was developed by Alfred Binet and Theodore Simon in the early 20th century as part of their development of the Binet-Simon Scale.

One measure that can be taken to solve the problems of gifted children is to offer them opportunities for acceleration, such as skipping grades or taking advanced classes.

Gifted children have a need for more challenging and stimulating educational experiences that can help them develop their talents and potential.

Verbal intelligence tests measure language-based abilities, such as vocabulary, comprehension, and verbal reasoning. Non-verbal or performance intelligence tests measure non-language-based abilities, such as spatial reasoning, perceptual speed, and visual-motor coordination.

Thorndike believed that intelligence is a combination of innate abilities, such as memory and attention, and learned abilities, such as problem solving and reasoning.

Backwardness in children may be caused by a combination of genetic and environmental factors. Genetic factors may include developmental disorders such as Down syndrome, while environmental factors may include poor nutrition, lack of early stimulation, and inadequate educational opportunities.