What Happened Before

Fossil trees were discovered in a sedimentary rock layer. In the rock layer below are fossils of clams, similar to clams that are currently found on the shores of the Gulf of Mexico. Based on this evidence, we could conclude that the area where the fossils were discovered had what sequence of climates in the past?

• Beach, followed by a forest

• Rocky and dry, then very moist

• Forest, and later a mountain

• Very cold area, then much warmer

Geologists discovered a layer of rock formed millions of years in the past. Which of the following would provide the best evidence of what the environment was like when the rock formed?

• The time when the rock appears to have formed

• The sediments from which the rock is made

• The fossil plants and animals found in the rock

• The kinds of rocks above and below the rock layer

Finding fossils of what kind of organism in the rock layers below a forest would lead to the conclusion that the area long ago had a large lake?

• Tall trees

• Small reptiles

• Flowering plants

• Freshwater fish

The tables here give information on animal and plant fossils. Based on the information in the tables, which two fossils would most likely be found together in the same rock?

• Fish skull and cactus

• Mouse skull and seaweed

• Alligator toe bone and fern

• Shark’s tooth and marsh grass

Fossils are best used as evidence about which of these?

• The processes that change rocks over time

• How best to conserve natural resources

• The plants and animals that lived long ago

• What forces drive the water cycle on Earth

Finding fossils in an area can help us learn what about that location?

• Which places in the region receive the most sunlight

• The effect of the climate on the formation of soil

• How modern plants and animals interact there

• The kinds of organisms that lived there long ago

An area is currently a forest. What evidence would best indicate that this area was covered by water millions of years ago?

• An increase in rainfall in the forest over time

• Presence of plants in the forest that need water to live

• Fossils of fish discovered in rocks below the forest

• Insects living in the forest that lay their eggs in water

This table gives information on different fossils. According to the information on the table, finding which fossil in a region would lead to the conclusion that the area was, long ago, covered with trees?

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Fossil ferns, like the ferns found in modern swamps, were discovered in a layer of rock. In a rock layer below were found the fossils of cactus, like those that live in hot, arid deserts today. Based on this evidence, we could conclude that the area where the fossils were discovered had what sequence of climates in the past?

• Forest, followed by deep ocean

• Cold climate that got warmer over time

• Rushing river, then a dark cave

• Very dry and then, much more damp

Herbivores are animals that eat plants. Finding many fossils of large herbivores in rocks that are millions of years old would lead to what conclusion about the ancient environment of an area? A reasonable conclusion is that the area was once a -

• rocky seashore

• thriving grassland

• frozen lake

• muddy swamp