Question

how life began origins nova neil degrasse tyson hd
during earths \heavy bombardment\ period, what was one of the consequences of impacting asteroids/comets?
they produced oxygen and formed an ozone layer
they cooled the planet by casting dust into space
they vaporized the oceans and melted the crust
they shielded earth from incoming radiation

Explanation:

During the "heavy bombardment" period, large - scale impacts from asteroids and comets had extreme effects. The energy from these impacts was so great that it could vaporize the oceans (due to the intense heat generated) and melt the Earth's crust. Oxygen production and ozone layer formation (first option) are more related to biological processes (like photosynthesis by early organisms) rather than asteroid/comet impacts. Casting dust into space to cool the planet (second option) is more associated with volcanic eruptions or large - scale fires on a much later, more stable Earth. Shielding from incoming radiation (fourth option) is not a consequence of these impacts; in fact, the impacts would have exposed the Earth to more chaos rather than shielding.

Answer:

They vaporized the oceans and melted the crust.