Compostable: Materials that break down into organic matter (humus, CO2, water) in a specific composting environment (industrial or home) within a set timeframe, leaving no toxic residue.Biodegradable: Materials that can be broken down by microorganisms. However, this term doesn't specify the timeframe or the environment required. A product might be "biodegradable" in marine environments over hundreds of years but not in a backyard compost pile.Bio-based: Materials made fully or partly from biomass (plants, corn starch, sugarcane, etc.), rather than fossil fuels. A bio-based plastic isn't necessarily biodegradable or compostable.It's crucial to look for certifications like ASTM D6400 (for industrial composting) or certifications for home composting (though these are less common) when considering "compostable" plastics.