Early Earth

Question 1

Earths atmosphere, oceans,and continents began to form during a period of Earths history called

Accepted Answer

Precambrian Time.

Question 2

A(n) ____________________ is a ball of dust and ice that orbits the sun.

Accepted Answer

comet

Question 3

Which gases made up most of Earth’s first atmosphere?

Accepted Answer

hydrogen and helium

Question 4

During early Precambrian Time, _______________ began to erode Earth’s rocky surface.

Accepted Answer

rain

Question 5

Scientists believe that the earliest life forms probably appeared about

Accepted Answer

3.5 billion years ago

Question 6

The earliest life forms were probably most similar to present-day

Accepted Answer

bacteria.

Question 7

Over time, the oceans affected the composition of the atmosphere by absorbing much of the

Accepted Answer

carbon dioxide

Question 8

What is the approximate age of Earth?

Accepted Answer

4.6 billion years old

Question 9

Which of the following was used to determine the age of Earth?

Accepted Answer

radioactive dating

Question 10

Processes changed some of the oxygen into ___blocked out deadly rays of the sun.

Accepted Answer

ozone

Question 11

Oceans formed from ____________.

Accepted Answer

rain water

Question 12

As organisms released oxygen into the air, the amount of oxygen

Accepted Answer

increased.

Question 13

A waste product of photosynthesis is

Accepted Answer

oxygen.

Question 14

Process where the continents slowly move over Earth's surface is

Accepted Answer

continental drift.

Question 15

The process by which organisms make their own food is called

Accepted Answer

photosynthesis.

Question 16

Scientists think that earth began as a ball of dust, rock, and _________ in space.

Accepted Answer

ice

Question 17

How would Earth's atmosphere be different if organisms capable of photosynthesis not evolved?

Accepted Answer

It would have no oxygen.

Question 18

Continents formed from?

Accepted Answer

Less dense rock at the surface

Question 19

How did Earth's second atmosphere mostly made of CO2, N, and H2o form?

Accepted Answer

volcanic eruptions and comets.

Questions 19