In what kind of reaction do two or more substances combine to form a new compound?
a. decomposition reaction
c. double-displacement reaction
b. ionic reaction
d. synthesis reaction

It is D. Synthesis Reaction.

There seem to be 3 major discoveries about particles that year. The first is neutrino oscillation is demonstrated. Next, supernovae observations suggest that the expansion of the universe is accelerating. Time reversal asymmetry is observed for K meson decay