The Magic School Bus :  Hasa Heart / 
Illustrated by Carolyn Bracken. 
 - USA :  Scholastic Inc.,  2005. 
 -  ill ;  23 cm. 
 - Scholastic Reader  Level 2 .
<br/><br/><label>ISBN: </label>0439684021 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Embryology