Educational worksheet explaining the four types of fossils with examples and images.

Let's solve the worksheet titled "Four Types of Fossils" step by step. The goal is to identify the correct type of fossil for each scenario based on the description and image.

There are four main types of fossils:

1. Mold fossil – A cavity or impression left in rock after an organism decomposes.
2. Cast fossil – A fossil formed when minerals fill a mold, creating a copy of the original organism.
3. Trace fossil – Evidence of an organism’s activity (e.g., footprints, burrows).
4. True form fossil – When the actual remains (like bones or shells) are preserved in their original form or replaced with minerals.

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Let's go through each one:

#### 1. First Image: Fish in stone
> *When this fish died, its body left an imprint in the mud. The body decomposed but the mold was filled with minerals that hardened into stone.*

- This describes a mold (imprint), then minerals filled it → cast.
- So, this is a cast fossil.

✔ Answer: This is a cast fossil.

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#### 2. Second Image: Dinosaur footprint
> *This footprint was left behind by a dinosaur who walked through soft mud millions of years ago. The dinosaur went on to live for many more years but his footprint was stuck in time.*

- This is evidence of activity, not the organism itself → trace fossil.

✔ Answer: This is a trace fossil.

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#### 3. Third Image: Frog in amber
> *A frog was trapped in sticky sap as it landed on a prehistoric tree. After a while, the sap dried and hardened into amber, preserving the entire frog inside.*

- The entire organism is preserved in resin (amber) → true form fossil.

✔ Answer: This is a true form fossil.

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#### 4. Fourth Image: Leaf in rock
> *This fern leaf fell into a mud puddle. The mud hardened and dried into rock and the fern leaf eventually decayed. All that is left is an imprint of where the leaf once was.*

- The leaf decayed, leaving only an impression → mold fossil.

✔ Answer: This is a mold fossil.

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#### 5. Fifth Image: Shell in sand
> *This shell left an imprint in the sand. After many years, the sand hardened to form rock. The shell was long gone, but the imprint was left in the rock.*

- Again, the shell decayed, leaving an impression → mold fossil.

✔ Answer: This is a mold fossil.

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#### 6. Sixth Image: Snake track in clay
> *As an ancient snake slithered through clay, it left behind this track. The snake moved on, but its track was preserved into rock.*

- This is evidence of movement, so it's a trace fossil.

✔ Answer: This is a trace fossil.

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#### 7. Seventh Image: Mineralized animal bones
> *When this animal died, its body decomposed and the minerals left behind were filled with minerals. The rocks that remain are the same shape and size as the bones were.*

- The original bone material was replaced with minerals → cast fossil (specifically, a replacement fossil, which falls under cast).

✔ Answer: This is a cast fossil.

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#### 8. Eighth Image: Mammoth frozen in ice
> *A mammoth died and its body was frozen in ice for thousands of years. Because it was frozen, the body could not decompose and was completely preserved.*

- The actual body is preserved → true form fossil.

✔ Answer: This is a true form fossil.

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Final Answers:

1. Cast
2. Trace
3. True form
4. Mold
5. Mold
6. Trace
7. Cast
8. True form

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Summary Table:

| Image | Description | Fossil Type |
|-------|-------------|-------------|
| 1 | Fish imprint filled with minerals | Cast |
| 2 | Dinosaur footprint | Trace |
| 3 | Frog in amber | True form |
| 4 | Fern leaf imprint in rock | Mold |
| 5 | Shell imprint in rock | Mold |
| 6 | Snake track in clay | Trace |
| 7 | Bones replaced with minerals | Cast |
| 8 | Mammoth preserved in ice | True form |

✔ All answers are now correctly identified!