Final answer:
The age of Earth is best estimated to be 4.56 billion years, using evidence from radiometric dating and understanding the formation of the solar system. This estimate is supported by the oldest rocks and fossil records on Earth.
Step-by-step explanation:
The best estimate for the age of Earth is 4.56 billion years (option e). Geological and astronomical evidence, such as radiometric dating, supports this age. The oldest rocks on Earth have been dated between 4 and 5 billion years old, and the oldest fossils indicate that life began around 3 to 4 billion years ago. Additionally, the age of the solar system, which includes Earth, is also estimated to be around 4.5 billion years, which corresponds to the time when the planets, including Earth, were formed.
It's important to note that these figures are incredibly different from early beliefs during Darwin's time, when people thought Earth was only around 6,000 years old. The discovery that Earth is billions of years old was a significant shift in understanding and influenced the development of the theory of evolution. Earth's history is vast, and to help with this, geologists use abbreviations like Ga (billions of years) to represent different periods in Earth's geological timeline.