Did Comets Bring Ingredients for Life to Earth?

Chemicals that could help make life’s building blocks. The first paragraph describes a proposal about chemicals, not living animals.

Clue: Comets are icy objects that travel through space. Some scientists have suggested that they brought important chemicals to the early Earth. These chemicals could help make the building blocks of life.

It would rarely reach the ground in a useful amount. The model suggests rare delivery, while the researchers cannot rule it out.

Clue: A Cambridge-led team used computer models to study one chemical found in comets. It says the chemical would rarely have reached the ground in a useful amount after a crash. The researchers cannot rule out a rare delivery.