Short answers, pulled from the story.
Intelligence has been defined in many ways, including the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as the ability to perceive or infer information and retain it as knowledge applied to adaptive behavior. When two dozen prominent theorists were once asked to define it, they gave two dozen somewhat different definitions.
The word intelligence derives from the Latin nouns intelligentia and intellēctus, which stem from the verb intelligere, meaning to comprehend or perceive. In the Middle Ages the word intellectus became the scholarly term for understanding and a translation of the Greek term nous.
The g factor, also called General Intelligence, is a construct that summarizes the correlations observed between a person's scores across a range of cognitive tests. First described in humans, it has since been identified in non-human species, accounting for 47% of the variance in cognitive ability among primates and between 55% and 60% in mice.
Learning is the act of retaining facts, information, or abilities and being able to recall them for future use. Intelligence is the cognitive ability of someone to perform those and other processes.
Beyond academic ability measured by IQ tests, intelligence includes emotional intelligence, the ability to read and convey emotions, social intelligence, the ability to understand social cues and motivations, and moral intelligence, the capacity to understand right from wrong. The contrast between book smarts and street smarts distinguishes academic knowledge from knowledge gained through practical experience.
Intelligence has been observed in non-human animals including chimpanzees, bonobos such as the language-using Kanzi, dolphins, elephants, parrots, rats, ravens, and cephalopods. Some researchers have argued that plants exhibit intelligence through sensing their environment and registering memories, though this remains controversial.