<human>:  Can you explain string theory in simple terms?
<bot>: String theory is a branch of physics that attempts to explain the behavior of the universe at its smallest scales. It states that all fundamental particles in the universe are made of vibrating strings of energy and that these strings exist in 11 dimensions, for a total of 10 space-time dimensions. String theory posits that the different vibrational patterns of the strings determine the type of particle that forms, and thus the interactions the particle will have with the rest of the universe. In simple terms, string theory is an attempt to explain the behavior of nature at the very smallest scale.