For decades, planetary scientists hypothesized that Earth's water was delivered primarily by carbonaceous chondrite meteorites during the planet's late accretion phase, pointing to isotopic similarities between the water on Earth and in these meteorites. Recently, however, researchers analyzing samples from the asteroid Itokawa discovered that solar wind implanting hydrogen ions into surface minerals could represent a significant, previously overlooked source of water. While this new mechanism explains how water could form on dry space rocks, it has not yet supplanted the meteorite delivery model. Instead, scientists are now exploring how both processes may have concurrently contributed to Earth's early oceans.
Which choice best describes the overall structure of the text?
- AIt compares two historical methods of data collection, argues that one method is superior to the other, and outlines steps to standardize this superior method.
- It describes a prevailing hypothesis, introduces a recent discovery that offers an alternative explanation, clarifies the current status of that discovery, and concludes with a potential integration of both views.Answer
- CIt details a widely accepted scientific theory, highlights a fundamental flaw in its methodology, proposes a replacement theory, and advocates for its immediate adoption.
- DIt presents an unresolved scientific mystery, proposes two mutually exclusive solutions, and demonstrates why neither solution is supported by empirical evidence.