Based on the worksheet provided, here are the answers to fill in the blanks.
Step-by-step Solution:
1.
First Blank (Definition of Tropism):
The sentence reads: "A tropism is the movement or growth of a plant as it responds to a stimulus in its environment. A \_\_\_\_\_\_\_ is anything that causes an action."
* *Reasoning:* In science, a "stimulus" is defined as something that evokes a specific functional reaction in an organ or tissue. The text actually gives the hint right before the blank by saying "...responds to a
stimulus".
* *Answer:*
stimulus
2.
Second Blank (Positive/Negative Tropism):
The sentence reads: "If the plant grows toward the light, this is a positive phototropism. If the plant grows away from the light, this is a \_\_\_\_\_\_\_ phototropism."
* *Reasoning:* The text explains that growing *toward* is "positive." Therefore, growing *away* is the opposite. The opposite of positive is negative.
* *Answer:*
negative
3.
Third Blank (Geotropism/Gravity):
The sentence reads: "When roots grow downward, they are exhibiting \_\_\_\_\_\_\_ geotropism."
* *Reasoning:* Geotropism (or gravitropism) is the response to gravity. Growing *downward* means growing in the direction of gravity's pull. Just like with light, growing toward the stimulus (gravity pulling down) is considered "positive."
* *Answer:*
positive
4.
Fourth Blank (Thigmotropism/Touch):
The sentence reads: "Vines usually show negative thigmotropism. Roots generally show positive thigmotropism when they touch rocks and other objects in the soil that get in their way. This helps them move around obstacles. Thigmotropism is a plant's response to \_\_\_\_\_\_\_."
* *Reasoning:* The paragraph heading is "Thigmotropism." The very first sentence of that section says: "Thigmotropism is a plant's response to
touch."
* *Answer:*
touch
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Final Answer:
1. stimulus
2. negative
3. positive
4. touch
Parent Tip: Review the logic above to help your child master the concept of plant tropisms worksheet.
