premise: if something is a stage in a process then that something is required for that process sent2: sedimentary rock is made of sediment sent3: if something changes to something else then that something else is formed from that something sent4: exposure to extreme heat and pressure changes / metamorphoses sedimentary / igneous rock into metamorphic rock sent5: the formation of metamorphic rock is a sequential process, with stages of rock being compacted, heated, recrystallized sent6: recrystallization is a kind of event sent7: if an event is required for a process then that event must occur before that process can occur sent8: formation in the rock cycle means an old class of rocks changes into a new class of rocks.
hypothesis: an algal bloom is a danger to fish because it decreases the oxygen levels in an environment