Many reef-building corals host photosynthetic algae, called zooxanthellae. Algae supply sugars; corals supply shelter and resources. Heat stress can cause algae loss and bleaching. Bleached does not mean dead. Acidification is a separate chemical change; lower pH does not necessarily mean pH below seven. Safety: No seawater, acids, shells, live organisms or reef visits. Stop: Stop at paper paths and evaluation. Do not mix acids, test shells or touch coral.

Materials: Paper; Pencil 1. Draw a coral polyp and algae dots inside its tissue. Add two benefit arrows: algae → coral, sugars; coral → algae, sheltered habitat and nutrients. Draw a second coral with fewer dots after heat stress. Explain that white skeleton becomes more visible, not that heat paints coral white. 2. Draw a separate chemistry path: atmospheric CO2 dissolves in seawater → carbonic acid forms in a reversible reaction → more hydrogen ions → lower pH and fewer carbonate ions. Label carbonate as material needed to build calcium carbonate skeletons. Reduced carbonate makes building harder; under corrosive conditions calcium carbonate can dissolve. 3. Copy an illustrative restoration comparison: Plan A grows and transplants nursery corals but leaves poor water quality and heat risk unchanged; Plan B combines nursery corals with water-quality improvement and survival monitoring, while wider emissions reduction is still needed. Choose a plan with a reason and name evidence needed before declaring success. 4. Add a habitat link: shallow coral reefs support an estimated quarter of marine species at some life stage. Explain why loss can affect shelter and feeding relationships, but does not prove every associated species instantly becomes extinct. State why restoration does not replace reducing the causes of damage. Done: Keep two distinct causal paths, both partner benefits and a restoration choice with a required outcome measure. Proof: Keep the coral sketch and proposal answer. Note help with chemistry terms or the chosen criterion. Stop: Stop at paper paths and evaluation. Do not mix acids, test shells or touch coral.