Cause and Effect — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Liam forgot to water the plant for two weeks. The leaves turned brown and fell off. What was the cause?
A) The leaves turned brown.
B) Liam forgot to water the plant.
C) The plant grew taller.
D) The leaves fell off.
The cause is the reason something happened. Liam forgetting to water the plant caused the leaves to turn brown.
2. Which signal word best completes this sentence? "The river flooded ___ it rained for five days straight."
A) so
B) therefore
C) because
D) as a result
The word 'because' connects the effect (river flooded) to the cause (rained for five days).
3. Sara left her crayons on the sunny windowsill. When she came back, they had melted. What was the effect?
A) Sara left her crayons on the windowsill.
B) The sun was shining brightly.
C) The crayons melted.
D) Sara came back to the room.
The effect is what happened as a result. The crayons melting was the effect of being left on the sunny windowsill.
4. Which sentence correctly shows a cause followed by an effect?
A) The bird flew away so the cat jumped at it.
B) The cat jumped at the bird so it flew away.
C) The bird and the cat played together.
D) Because the bird flew, the cat sat still.
This sentence shows the cause (cat jumped at bird) followed by the signal word 'so' and the effect (bird flew away).
Part B: Fill in the Blank
Write the correct answer on each line.
1. The squirrel gathered acorns because winter was coming soon.
The word 'because' connects the effect (gathered acorns) to the cause (winter was coming).
2. Nobody could hear the speaker. Therefore, she turned up the microphone.
The word 'Therefore' introduces the effect (turned up the microphone) caused by no one being able to hear.
3. The students did not study. As a result, many of them failed the quiz.
The phrase 'As a result' signals the effect (failed the quiz) caused by not studying.
4. When the fire alarm rang, everyone walked outside in a single line.
The word 'When' introduces the cause (fire alarm rang) that led to the effect (everyone walked outside).
5. The bridge was closed for repairs, so drivers had to take a detour.
The word 'so' signals the effect (drivers took a detour) that followed the cause (bridge closed for repairs).