New research suggests “microlightning” exchanges among water droplets in Earth’s early atmosphere may have sparked the building blocks of life.

This test could help. Using the key below, answer the questions based on how strongly you agree or disagree with the statement.

For example, if you take a pregnancy test too early, you could get a false-negative result because your body isn’t producing enough human chorionic gonadotrophin (HCG) yet. To ensure you get the most ...