LEVEL4 3
Quiz 13 Which part of our body growls besides the stomach？ 3
Quiz 14 Can people move their ears？ 7
Quiz 15 Why do some people have freckles？ 11
Quiz 16 Why do your hands get wrinkled in water？ 15
Words Review 4 19
LEVEL5 23
Quiz 17 Why do we have the wrinkles on our elbows？ 23
Quiz 18 How long does it take gum to digest inside your stomach？ 27
Quiz 19 Why do girls grow faster than boys？ 31
Quiz 20 How many permanent teeth does an adult normally have？ 35
Words Review 5 39
LEVEL6 43
Quiz 21 Can sweat come out of our belly buttons,too？ 43
Quiz 22 Which finger is the most sensitive？ 47
Quiz 23 How often do most people pass gas a day？ 51
Quiz 24 How long do fingernails grow in a year？ 55
Words Review 6 59
Answers 61
Workbook 65