Final Answer:
Failure to receive adequate sensory stimulation during a critical or sensitive period can result in permanent sensory deficits.
Step-by-step explanation:
The term that fits in the blank is "critical" or "sensitive." The critical or sensitive period refers to a specific timeframe during development when an organism is particularly sensitive to certain environmental stimuli. During this period, sensory systems are actively developing, and exposure to appropriate stimuli is crucial for the normal maturation of these systems.
Failure to receive adequate sensory stimulation during the critical or sensitive period can result in permanent sensory deficits. For example, in visual development, if a child does not receive proper visual input during the critical period, it may lead to irreversible visual impairments. This concept is applicable to various sensory modalities, emphasizing the importance of timely and appropriate stimulation for normal sensory development.