Comets probably did not bring to Earth the materials necessary for the origin of life": the origin of life is not on Earth, but on Mars.
"Scientists from the University of Cambridge discovered that comets probably could not have supplied enough organic compounds to Earth for the origin of life. Computer models showed that most of these molecules, particularly hydrogen cyanide, were destroyed as they passed through the atmosphere and collided with the Earth's surface. In addition, cometary bombardment of Earth weakened rapidly in the first 500 million years of its existence.
At the same time, Mars can be a more suitable place to supply the necessary materials: due to the thin atmosphere and lower gravity, more comets can reach its surface. Therefore, scientists admit that life originated on the Red Planet, although they do not rule out that it did not happen either on Earth or on Mars."