What would most likely happen if airborne pollution blocked the sun’s rays so significantly that only 5% of plants survived?
1 . The atmosphere would fill with carbon dioxide, and animals would begin to die.
2. The atmosphere would fill with oxygen, and animals would begin to die.
3. All animals would evolve to use a mixture of oxygen and carbon dioxide during respiration.
4. All animals would evolve to begin using carbon dioxide as a food source
