Selectivity refers to the ability to choose or focus on specific items or information while ignoring others. This concept is important in various fields, such as psychology, where it describes how individuals prioritize certain stimuli over others in their environment. For example, when studying, a person may exhibit selectivity by concentrating on key concepts while disregarding distractions. In the context of biology, selectivity can describe how certain organisms or cells respond to specific signals or substances. For instance, neurons in the brain selectively transmit signals based on the type of neurotransmitter they receive, allowing for precise communication within the nervous system.