Detailed Instructions: In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it. Your job is to determine which sentence(s) from the passage can be used to search for further information needed to answer the question.
Problem:Question: What's the average lifespan of the animal that has a jaw with properties similar to those that probably led to the evolution of baleen? Passage:The oldest true fossils of baleen are only 15 million years old because baleen rarely fossilizes, and scientists believe it originated considerably earlier than that. This is indicated by baleen-related skull modifications being found in fossils from considerably earlier, including a buttress of bone in the upper jaw beneath the eyes, and loose lower jaw bones at the chin. Baleen is believed to have evolved around 30 million years ago, possibly from a hard, gummy upper jaw, like the one a Dall's porpoise has; it closely resembles baleen at the microscopic level. The initial evolution and radiation of baleen plates is believed to have occurred during Early Oligocene when Antarctica broke off from Gondwana and the Antarctic Circumpolar Current was formed, increasing productivity of ocean environments. This occurred because the current kept warm ocean waters away from the area that is now Antarctica, producing steep gradients in temperature, salinity, light, and nutrients, where the warm water meets the cold.

Solution:
Baleen is believed to have evolved around 30 million years ago, possibly from a hard, gummy upper jaw, like the one a Dall's porpoise has; it closely resembles baleen at the microscopic level