Extinction of taxa is difficult to detect as long gaps without a sighting is not definitive, but before 1995 a threshold of 50 years without a sighting was used to declare extinction.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request. ### Instruction: List the MITRE techniques contained in the text. ### Input: Extinction of taxa is difficult to detect as long gaps without a sighting is not definitive, but before 1995 a threshold of 50 years without a sighting was used to declare extinction. ### Response: .