What is used to measure the density of the earths layers

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

What molecules does hemoglobin decay into over time

Astudent completed a lab report. which correctly describes the difference between the “question” and “hypothesis” sections of her report? “question” states what she is asking, and “hypothesis” states the result of her experiment. “question” states what she is asking, and “hypothesis” states what she thinks the answer to that question is in “if . . then . . because” format. “question” describes what she is trying to find out, and "hypothesis" states the procedures and methods of data collection. “question” describes what she is trying to find out, and “hypothesis” states any additional information or prior knowledge about the question.