External and Internal Stimuli
Organisms and Environments
INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have
learned about external and internal stimuli. Words may be used more than once or not used at
all.
Word Bank
reaction
External
predator
fight
prey
stimulus
internal
Sun
CLOZE 1
A ____________________ is something that causes an action to happen.
_____________________ stimuli are stimuli that begin outside the organism’s body. The
__________________ is the stimulus that causes phototropism in plants. In animals, the
presence of a _________________ will cause prey to flee for safety. The prey fleeing is the
__________________ to the stimulus of the predator. When a resource, such as food, is the
stimulus, then the response between competing organisms is to ___________________ over
the resource.
1
External and Internal Stimuli
Organisms and Environments
INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have
learned about external and internal stimuli. Words may be used more than once or not used at
all.
Word Bank
bacteria
external
sweating
fever
homeostasis
Vomiting
wilt
internal
CLOZE 2
An ___________________ stimulus is one that originates inside an organism’s body. If a
plant doesn’t have enough water in its body cells, then the lack of water causes the plant to
________________. In animals, some illnesses are caused by internal stimuli.
__________________ is the response to motion sickness, food poisoning, or pregnancy.
When the body temperature rises above the normal limits, the organism is said to have a
_________________. Internal stimuli that cause a rise in the body temperature include
viruses, ______________________, fungi, toxins, or drugs. Internal stimuli affect the
_________________, or stability, of the internal environment in organisms.
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