Chapter 4 Lesson 1

everything that surrounds a living thing

• environment
• stimulus
• response
• reaction

anything that causes a living thing to react

• environment
• stimulus
• response
• surroundings

 a reaction to a stimulus

• environment
• internal stimulus
• response
• external stimulus

anything in an organism's environment that causes it to react

• internal stimulus
• external stimulus
• reaction
• senses

anything within an organism that cause it to react

• external stimulus
• environment
• response
• internal stimulus

Shivering when you feel cold is a ______.

• response
• stimulus

Plants growing toward the light is an example of an

• internal stimulus
• external stimulus

Hunger pains are an example of an _______.

• internal stimulus
• external stimulus

After hearing a loud sound, you cover your ears.  The sound is a/an

• internal stimulus
• external stimulus

After hearing a loud sound, you cover your ears.  Covering your ears is a/an 

• stimulus
• response