What period is times when certain internal and external influences have a major impact on development called?

The period when certain internal and external influences significantly impact development is called a "critical period." During this time, specific experiences or environmental factors can have profound effects on an individual's growth and development. For example, critical periods are often discussed in the context of language acquisition or emotional attachment in early childhood. If certain stimuli are not encountered during these Windows, it may be difficult or impossible to develop those skills later on.