A volcanic ash layer between sedimentary rock layers is used by geologists to 1. Determine the absolute age of the Earth

2. Predict global warming

3. Locate an earthquake epicenter

4. Correlate widely separated sedimentary rock layers

What is the mass of 8 moles of sodium atoms

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

What is the percentage of hydrogen in c2h4