Final answer:
External ballistic evidence like gunpowder residue or meteorites needs to be collected immediately after an event due to their fragile nature. In forensic science, this ensures the preservation of evidence. Meteorites in Antarctica are preserved by ice and collected for scientific study.
Step-by-step explanation:
The type of ballistics that needs to be collected immediately because it is so fragile refers to external ballistic evidence such as gunpowder residue on the surfaces around the area where a gun was fired. In crime scene investigations, this type of evidence can be easily lost or contaminated due to environmental factors or human activity. Therefore, forensic teams aim to collect this evidence as quickly as possible after the event. In a broader scientific context referenced in the provided information, meteorites that fall to Earth could be considered a type of 'ballistic' evidence. These celestial objects need to be collected immediately after they fall, or like the Antarctic samples preserved in ice, they must be maintained in a nearly pristine state to protect their scientific value. Table 14.2 mentioned would likely categorize the frequencies of meteorite occurrences based on how they are discovered: as a 'fall', 'find', or preserved in Antarctic ice.