What happens when a covalent bond forms?

the two atoms share the electrons equally between them.
the metal atom loses electrons to the nonmetal atom.
one nonmetal atom takes electrons from another nonmetal atom.
two nonmetal atoms transfer electrons.

Why do oceanic plates tend to subduction when colliding with a continental plate

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

Which of the following is a limitation of a clinical trial? a.)amount of random assignments b.)hospital cost c.)number of test tubes d.)amount of peer review