La molécule du trioxyde de diazote est formée de : Trois atomes d’oxygène et un atome d’azote?
Un atome d’azote et deux atomes d’oxygène?
Deux atomes d’azote et trois atomes d’oxygène?

Road users moving into your lane, brake lights, and abrupt changes in road surface are a. rare at night b. indicators of potential hazards c. not worth worrying about before you reach them d. no problem for experienced drivers

Observations show that interstellar clouds can have almost any shape and

When the displacement of a mass on a spring is 12a the half of the amplitude, what fraction of the mechanical energy is kinetic energy? at what displacement, as a fraction of a, is the mechanical energy half kinetic and half potential?