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Table of Contents

1

Investigation 1: Origin of Seeds

3

The Reason for Fruit

3

The Most Important Seed

8

Barbara McClintock

12

Nature Journal—How Seeds Travel

16

Investigation 2: Growing Further

22

Germination

22

Life Cycles

26

Investigation 3: Meet the Crayfish

34

Crayfish

34

Adaptations

42

Life on Earth

50

Inside a Snail’s Shell

64

A Change in the Environment

66

Food Chains

70

Investigation 4: Human Body

74

The Human Skeleton

74

Barn Owls

78

Fossils

81

Skeletons on the Outside

89

Crayfish, Snails,and Humans

91

Your Amazing Opposable Thumbs

93

Joints and Muscles

94

Fingerprints

100

Supertwins

104

References

106

Science Safety Rules

106

Glossary

107

Index

110