Statement 1 is correct: Volcanic action releases carbon dioxide trapped within the Earth's crust and mantle. Statement 2 is correct: Respiration releases carbon dioxide as a byproduct of cellular respiration in living organisms. Statement 3 is incorrect: Photosynthesis removes carbon dioxide from the atmosphere. Plants and other photosynthetic organisms use carbon dioxide during photosynthesis to create organic molecules. Statement 4 is correct: The decay of organic matter releases carbon dioxide as decomposers break down dead plants and animals. This process returns carbon stored in organic matter back to the atmosphere as carbon dioxide.