Answer:
In chemistry the reactivity series is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to the lowest.
C, because a homogeneous mixture is evenly mixed.
All those others would be heterogeneous (not evenly mixed).
Space -filling models are also known as Calotte models. These are 3 dimensional models that depict the spatial relationships between atoms.
The space-filling model of water molecule shows the 3 D structure of the water molecule. This model CLEARLY REVEALS THE OXYGEN ATOM WHICH IS LOCATED CENTRALLY WITH TWO HYDROGEN ATOMS IN THE ADJACENT SIDES. THE MODEL ALSO SUGGESTS HOW THE WATER MOLECULES ATTRACT EACH OTHER.
