The graph below shows the diversity of organisms over a period of Earth's history. What do we call the events on the graph marked 1-5? According to the graph, which event caused the greatest decrease in the diversity of organisms?

5.1 The events on the graph marked 1-5, which show sharp decreases in the diversity of organisms, are called mass extinctions. Mass extinctions 5.2 Step 1: Analyze the approximate decrease in diversity for each event from its peak before the drop to its lowest point after the drop. • Event 1: Peak around 480 families, drops to around 380 families. Decrease ≈ 100 families. • Event 2: Peak around 520 families, drops to around 380 families. Decrease ≈ 140 families. • Event 3: Peak around 450 families, drops to around 300 families. Decrease ≈ 150 families. • Event 4: Peak around 420 families, drops to around 200 families. Decrease ≈ 220 families. • Event 5: Peak around 680 families, drops to around 500 families. Decrease ≈ 180 families. Step 2: Identify the event with the greatest decrease. Event 4 shows the largest approximate decrease in the number of families. Event 4 5.3 Volcanic eruptions release large amounts of ash and gases like sulfur dioxide into the atmosphere. This blocks sunlight, leading to a significant drop in global temperatures (volcanic winter) and reduced photosynthesis. The collapse of primary producers disrupts food chains, causing many species to starve. Toxic gases and acid rain also directly harm organisms and ecosystems. 5.4 Two other theories for the decrease in diversity of organisms at event marked 5 are: 1. Asteroid impact: A large asteroid striking Earth could cause widespread destruction, tsunamis, and eject vast amounts of dust and debris into the atmosphere, blocking sunlight and leading to global cooling. 2. Significant climate change: Rapid and drastic shifts in global temperatures (either warming or cooling) or sea levels could alter habitats faster than species can adapt, leading to widespread extinctions. 1. Asteroid impact, 2. Significant climate change That's 2 down. 3 left today — send the next one.