1. radioactive decay occurs when atoms

A- lose mass *
B- join with atoms of another element
C- break down to form atoms of another element
D- are exposed to chemical weathering

2. if you want to consult the geologic time scale for when the first vertebrates evolved, where would you look?
A- in the section for the Ordovician period of the paleozoic era.
B- in the section for the quaternary period of the cenozoic era.
C- in the section for the triassic period of the mesozoic era.
D- in the section for precambrian time. *

3. Earths atmosphere, oceans, and continents began to form during the first several hundred million years of.
A- precambrian time
B- the paleozoic era.
C- the mesozoic era *
D- the cenozoic era

4. During the devonian period, animals that could live on land began to evolve. these animals still spent part of there lives in the water. what where these animals called?
A- trilobites.
B- reptiles.
C- amphibians.
D- dinosaur. *

5. which of the following events occurred during the mesozoic era?
A- dinosaurs became common on lane. *
B- whales and dolphins evolved in the ocean.
C- reptiles evolved on land.
D- the supercontinent Pangaea formed.

6. which of the following vertebrates had the chance to become abundant after the dinosaurs became extinct?
A- woolly mammoths.
B- amphibians.
C- mammals. *
D- reptiles.

7. which of the following organisms is not extinct?
A- the dodo bird. *
B- the saber-tooth tiger.
C- the saltwater crocodile.
D- the Carolina parakeet.

8. During which section of the geologic time scale did the first modern humans evolved?
A- during the paleogene period of the cenozoic era.
B- during the quaternary period of the Cenozoic era.
C- during the cretaceous period of the mesozoic era.
D- during precambrian time. *

9. if a geologist found two fossil of different species buried next to each other in a rock layer, he or she might hypothesize that the two organisms may have been alive during the same time period?
-True *
-False

10. a species might become extinct when a disastrous event, such as a meteorite impact, occurs.
-True *
-False

1. The answer is C- break down to form atoms of another element. This process is known as radioactive decay, where the nucleus of an unstable atom breaks apart and transforms into a different element.

2. The answer is D- in the section for Precambrian time. The geologic time scale is divided into different periods and eras, and the Precambrian time refers to the earliest period in Earth's history, where the first vertebrates evolved.

3. The answer is A- Precambrian time. The formation of Earth's atmosphere, oceans, and continents happened during the early stages of Earth's history, which is classified as the Precambrian time.

4. The answer is C- amphibians. During the Devonian period, animals known as amphibians started to evolve. Amphibians are vertebrates that can live both on land and in water, which is why they still spent part of their lives in the water during this time.

5. The answer is A- dinosaurs became common on land. The Mesozoic era is often referred to as the "Age of Dinosaurs" because this is when dinosaurs became dominant on land.

6. The answer is C- mammals. After the extinction of the dinosaurs, mammals had the opportunity to thrive and become abundant. This led to the diversification and evolution of various mammalian species.

7. The answer is A- the dodo bird. Among the given options, the dodo bird is the only organism that is extinct. The other options, such as the saltwater crocodile, are still living species today.

8. The answer is B- during the Quaternary period of the Cenozoic era. The first modern humans (Homo sapiens) evolved during the Quaternary period, which is the most recent period in the geologic time scale.

9. The answer is True. If a geologist finds two fossils of different species buried next to each other in the same rock layer, it suggests that these two organisms might have coexisted during the same time period. This hypothesis is based on the principle of fossil succession, which states that different organisms lived in different time periods.

10. The answer is True. A species can become extinct due to various disastrous events, including meteorite impacts. These catastrophic events can cause significant environmental changes and disruptions, leading to the extinction of certain species.