Earths early history

Which is the original source of atmospheric oxygen?

What is the approximate age of the earth?

In what era did humans appear?

Which type of fossil will reveal the skin color of a 90 million year old frog?

Which is NOT a part of the mesozoic era?

Nearly all fossils occur in ______ rock.

Which gas most likely was NOT a part of Earth's early atmosphere?

The method used to determine the age of rock by comparing them with those in other layers is__.

Which is part of the endosymbiont theory?

Which of the following is not a part of the paleozoic era?

The longest period of time is_____.

Which describes what scientists believe Earth's appearance was like 4.5 billion years ago?

A mass extinction that included the disappearance of dinosaurs occurred during the____.

Something that does not need to be explained in an acceptable theory about the origin of life.

Which era of Earth's history could be named the era of mammals?

Louis Pasteur designed an experiment to show ___ was true even for microorganisms.

Which is the first era of Earth's history?

The amount of time it takes for half the original isotope to decay is ________.

What describes the idea of spontaneous generation?

Which of the following is not part of the cenozoic era?

Life coming from life is___________

A _________Consists of one or more periods.

Simple organic molecules could be formed from a mixture of gases when sparked by lightening,

The preservation of an organism is a _______.

Which explains why oxygen was absent in Earth's early atmosphere?