which best describes a gamma ray?

a. an energy ray with no mass and no charge

b. a positively-charged ray of light and protons

c. a negatively-charged ray of light and electrons

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere,b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify,d)anaerobic bacteria kept thriving with more oxygen

Some tools have graduations to show multiple measurements. for example, a ruler may have graduations for both millimeters and centimeters. when measuring the length of an earthworm, which graduations would allow for the most accurate measurement? millimeters centimeters decimeters meters