Which sentence describes how fusion occurs in stars?
A. High temperatures and pressures in a star's core cause atoms to
combine into new atoms, releasing energy.
B. Convection inside a star causes hydrogen and helium atoms to
collide and form larger atoms, releasing energy.
C. The gravitational force acting between two stars causes atoms in
their cores to split apart when they collide, releasing energy.
D. High pressure inside a star causes hydrogen and helium atoms to
collide and split apart, releasing energy.