In the context of organic chemistry, when are the first organic molecules thought to have existed?

• A. Approximately $3.5 \mathrm{billion} \mathrm{years} \mathrm{ago}$
• B. Approximately $500 \mathrm{million} \mathrm{years} \mathrm{ago}$
• C. Approximately $100 \mathrm{million} \mathrm{years} \mathrm{ago}$
• D. Approximately $1 \mathrm{billion} \mathrm{years} \mathrm{ago}$

Answer: (A)

Verified step by step guidance

1. Understand the context of the question: It is asking about the timeline of the existence of the first organic molecules on Earth.
2. Consider the history of Earth: Earth is approximately 4.5 billion years old, and life is thought to have begun relatively early in its history.
3. Recognize the significance of organic molecules: Organic molecules are essential for life, and their formation is a key step in the development of life on Earth.
4. Research scientific evidence: Studies of ancient rocks and fossils suggest that life, and thus organic molecules, existed around 3.5 billion years ago.
5. Evaluate the options given: Compare the timeline of Earth's history and the emergence of life to the options provided to determine the most scientifically supported answer.