Which type of molecule contains two atoms bonded together A) simple molecule
B) crystal
C) polymer
D) complex molecule

simple molecules contain two atom bonded together

 Simple Molecule

Explanation:  Ambigous question.  What is the scientific definition of "simple molecule?"  More by process of elimination than actual difinition, this is a simple molecule.  It takes a minum of two atoms to make a molecule (by definition).  A crystal is a collection of molecules, a polymer is a chain of molecules, and a complex molecule is, er  . ., complex.  The only reasonable, and best, answer is "simple molecule."

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.