SEMESTER 1 FINAL 2021

According to scientists, both Earth and moon are...

• About 1.6 Billion Years Old
• About 4.6 Billion Years Old
• About 9.6 Billion Years Old
• About 14 Billion Years Old

The composition of todays atmosphere is mostly...

• Hydrogen

• Oxygen

• Nitrogen

• Helium

If you know the age of a rock, you know the relative age of the _________________ that was found inside.

• sticky tar

• fossil

• amber

• ice

In what way can scientists determine the ages of fossils?

• relative dating
• radioactive dating
• law of superposition
• All of the above

In layers of sedimentary rock, the _________ layer is usually at the bottom. Each higher layer is _________ than the layers below it.

• oldest, younger
• youngest, older
• youngest, younger
• oldest, older

Scientists use unstable elements that decay, called _________ elements, to determine the actual age of a fossil.

• radioactive
• cation
• anion
• petrified 

What is the half-life of a radioactive element?

• How old it is when it is middle aged
• The time it takes for half of the atoms to decay
• The time it takes for half of the atom to form
• How old it is when the Earth is middle aged

The millions of fossils that scientists have collected are called

• The Geologic Time Scale
• The Origin of Species
• The Fossil Record
• A really neat fossil collection

What is a mass extinction?

• the extinction of all of Earth's species at ones time
• the extinction of many types of organisms at the same time
• the end of days
• the creation of many species at one time

Which of these describes a species that has become extinct?

• fewer members of the species are dying than being born
• more members of the species are dying than being born
• very few members of a species are alive
• all members of a species have died