When describing metallic bonding, scientists note that the metal ions seem to be floating in a sea of electrons. this arrangement contributes to the physical property of in metals

a) luster
b) ductility
c) malleability
d) conductivity

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)