Considering the age of the Earth and that the half-life of the isotope uranium-238 (238U) is 4.5 billion years, and assuming no additional 238U was produced after the Earth formed, approximately what fraction is left on Earth?
A. one-third
B. none
C. eighty percent
D. half
Answer: D
You might also like to view...
Why is heat often added to chemical reactions performed in the laboratory?
A. to increase the rate at which reactant collide B. to allow a greater number of reactants to pass over the activation energy C. to compensate for the natural tendency of energy to disperse D. all of the above
Several Gulf states have immense oil reserves and production capacity, but other countries in Southwest Asia and North Africa have little or none
Indicate whether the statement is true or false
The first trophic level in a hydrothermal vent community is ________.
A. dependent on organic material drifting down from the surface B. made up of clams and tube worms C. seriously polluted D. dependent on bacteria and their ability to use hydrogen sulfide E. provided by larvae drifting in deep-sea currents
North Carolina’s _______________ extends farther into the path of many Atlantic hurricanes than anywhere else on the East Coast
Fill in the blank with correct word.