PROBLEM 6. Hor?/w7jes Help Regulate Cell Activities 259 



/// UNIT V yon zvill consider these proble?ns: 



Problem i. What Are the Simplest Forms of Behavior in Ani- 

 mals? 



Problem 2. What Makes Complex Behavior Possible in Many- 

 celled Animals? 



Problem 3. How Does the Behavior of Complex Animals 

 Diifer from That of Simpler Forms? 



Problem 4. How Do Plants Respond to Their Environment? 



