Question

1. which process do scientists believe brought water to the earth

stars crashing into the planet
random water molecules released from the big bang falling on the earth during its formation
free hydrogen and free oxygen present in the early atmosphere combing because of earths cooling to form oceans and rivers.
water present in meteorites, comets and asteroids colliding with the earth.

Explanation:

Scientists believe that water on Earth was brought by meteorites, comets, and asteroids that collided with the planet. These celestial bodies contain water - ice. Stars crashing into the planet is not a source of Earth's water as stars are extremely hot and not carriers of water in the form we know. Water molecules from the Big - Bang falling on Earth during its formation is not a well - supported theory. Also, free hydrogen and free oxygen in the early atmosphere combining due to Earth's cooling is not the main process thought to bring water to Earth.

Answer:

Water present in meteorites, comets and asteroids colliding with the earth.