1．THE PLANTS ON MARS 1
2．THE CITY THAT GREW IN A LAKE 3
3．THE FISH ON THE MOUNTAIN 6
4．THE LEAF THAT TELLS A STORY 9
5．LIFE IN THE SOIL 11
6．WHAT ARE HUMANS 14
7．HOW THE SPECIES WERE RELATED 17
8．THE EYES 19
9．A RIVER OF ICE 22
10．THE RIVER DELTA 24
11．THE MOVING HILL 27
12．ELECTRICITY 29
13．A HORSE NO BIGGER THAN A CAT 32
14．THE NEVER-ENDING CYCLE 34
15．DESTROYED WET LANDS 36
16．A STONE FOR A SHEEP 39
17．A WAY TO REMEMBER 41
18．TEARS 44
19．THE ROPE STRETCHERS 46
20．LEARNING FROM PREHISTORIC PEOPLE 48
21．SOMETHING FOR NOTHING 51
22．MAGNETIC FIELD 53
23．THE ANIMAL WITHOUT A HEAD 57
24．FEWER BIRTHS 59
25．SIXTEEN LEFT FEET 62
26．A LEG WALKING RIGHT 64
27．HOW TO EXERCISE 66
28．NOT MADE FOR SWIMMING 69
29．THE FROG THAT CHANGES COLOR 72
30．WHAT IS SOIL MADE UP OF 75
31．DOES YOUR SKIN FIT 78
32．EAR AND SOUND 80
33．PYTHON,THE WORLD'S LONGEST SNAKE 82
34．PET FROM THE STONE AGE 85
35．WATER 88
36．THE COMPASS 91
37．WATER OFF A DUCK'S BACK 94
38．THE LAND OF DRIPPING WATER 97
39．GREEN PLANTS MAKE FOOD 100
40．A NEW KIND OF FARM 103
41．HURAKAN,GOD OF THE BIG WIND 105
42．WEATHER THE WAY WE WANT IT 107
43．THE RIVER IN THE OCEAN 110
44．ONE KILOMETRE IN THREE SECONDS 112
45．COMPUTER 114
46．HOW TO FIND FISH IN THE OCEAN 117
47．AIR 120
48．POLLUTED WATER SUPPLIES 123
49．A THREAD 100 MILES LONG 126
50．THE COLOR OF THE SMOKE 128
51．AIDS VIRUS 131
52．LIGHT 134
53．HOW HEAT TRAVELS 137
54．WHAT COLOR IS THE SUNLIGHT 140
55．BIRDS 143
56．THE ROLES OF YOUR BRAIN 145
57．KINETIC ENERGY AND POTENTIAL ENERGY 148
58．COMPUTER VIRUSES 151
59．SATELLITES 154
60．INSECTS 156
KEY TO EXERCISES 159
APPENDIX 162