To perform uranium - 235 dating on a sample comma what must be true?

To perform uranium-235 dating on a sample, it must contain uranium-235 and a measurable amount of its decay products, particularly lead-207. The sample should have remained in a closed system, meaning no loss or gain of uranium or lead has occurred since its formation. Additionally, the age of the sample should ideally fall within the effective dating range of uranium-235, which is typically millions to billions of years.