1. Intelligence is defined as the ability to learn, reason, problem solve, and think abstractly. It can be observed in humans, animals and plants.
2. There are many types of intelligence including linguistic, logical-mathematical, spatial, bodily-kinesthetic, musical, interpersonal, intrapersonal, and naturalist.
3. Factors that influence human intelligence include genetics, health, gender, education, poverty level, and environment. Intelligence is often measured using IQ tests.