Angiosperms are thought to have originated about __________ years ago.

• A. 2 billion
• B. 500 million
• C. 65 million
• D. 140 million

Answer: (D)

Verified step by step guidance

1. Understand the context: Angiosperms, also known as flowering plants, are a major group of plants that dominate most terrestrial ecosystems today. They are distinct from gymnosperms due to their flowers and fruit-covered seeds.
2. Recall the timeline of Earth's history: The origin of angiosperms is a significant evolutionary event. It occurred during the Mesozoic Era, specifically in the Cretaceous period, which began approximately 145 million years ago.
3. Eliminate incorrect options: 2 billion years ago is far too early, as this predates the evolution of multicellular life. 500 million years ago corresponds to the Cambrian Explosion, which is when many animal phyla first appeared, not angiosperms. 65 million years ago marks the end of the Cretaceous period and the extinction of dinosaurs, which is too recent for the origin of angiosperms.
4. Focus on the correct timeframe: Fossil evidence and molecular data suggest that angiosperms originated approximately 140 million years ago, aligning with the Cretaceous period.
5. Conclude: The correct answer is 140 million years ago, as this is supported by both paleontological and genetic evidence.