Correct Response: A. Bowen's reaction series is a system that identifies the temperature at which specific minerals in a cooling magma will solidify. The system helps geologist approximate the thermal conditions that an igneous rock formed under based on the specific minerals it contains. The rate at which minerals grow in a cooling magma (B) is determined by the chemistry of the magma and the rate that the temperature and pressure of the magma change during cooling. Bowen's reaction series does not account for changes in the mineral composition of rocks that occur after the magma solidifies (C) and it does not define which crystal systems that the minerals in a magma will crystallize into (D).