| Unit 1 |
4 |
How do people breathe? |
| Unit 2 |
6 |
What is the “Forehead of the Sky”? |
| Unit 3 |
8 |
Do alligators have a voice? |
| Unit 4 |
10 |
What is the first lady’s job? |
| Unit 5 |
12 |
Is slime good to eat? |
| Unit 6 |
14 |
How did the Liberty Bell become cracked? |
| Unit 7 |
16 |
What are fossils? |
| Unit 8 |
18 |
Who is Sandra Day O’Connor? |
| Unit 9 |
20 |
What is a snow eater? |
| Unit 10 |
22 |
Why did Native Americans make totem poles? |
| Unit 11 |
24 |
How are ladybugs useful? |
| Unit 12 |
26 |
What is a barn raising? |
| Unit 13 |
28 |
Does a giant redwood tree have giant roots? |
| Unit 14 |
30 |
What is it like to live on a houseboat? |
| Unit 15 |
32 |
How does a dragonfly use its legs? |
| Unit 16 |
34 |
What is a love apple? |
| Unit 17 |
36 |
Does it ever snow in the desert? |
| Unit 18 |
38 |
Who was Laika? |
| Unit 19 |
40 |
What are Saturn’s rings? |
| Unit 20 |
42 |
How do Americans thank veterans? |
| Unit 21 |
44 |
What are lantern fish? |
| Unit 22 |
46 |
How did stories about mermaids start? |
| Unit 23 |
48 |
How does an earthworm dig tunnels? |
| Unit 24 |
50 |
What are the Mayan pyramids? |
| Unit 25 |
52 |
What are feral animals? |
| Unit 26 |
54 |
What are the blues? |
| Unit 27 |
56 |
How can scents change the way you feel? |
| Unit 28 |
58 |
Who was the first African American nurse? |
| Unit 29 |
60 |
Why do groundhogs dig up fields? |
| Unit 30 |
62 |
Who are the ama? |
| Unit 31 |
64 |
Does music charm snakes? |
| Unit 32 |
66 |
What was the riddle of the sphinx? |
| Unit 33 |
68 |
What are ant colonies? |
| Unit 34 |
70 |
Who was Frederick Douglass? |
| Unit 35 |
72 |
How do animals know the way home? |
| Unit 36 |
74 |
What is a mannequin? |
| Unit 37 |
76 |
How can people save water? |
| Unit 38 |
78 |
What art has lasted for 25,000 years? |
| Unit 39 |
80 |
What are musk oxen? |
| Unit 40 |
82 |
Has anyone ever gone to the North Pole alone? |
| Unit 41 |
84 |
Why is the baobab tree special? |
| Unit 42 |
86 |
What is Space Camp? |
| Unit 43 |
88 |
What is the mystery of the monarch? |
| Unit 44 |
90 |
What is a neighborhood island? |
| Unit 45 |
92 |
What are the northern lights? |
| Unit 46 |
94 |
Who was Jim Henson? |