CBSE Class 7 Science Worksheet Set K - Free Printable

Problem Analysis:

The task involves filling in the blanks and determining whether statements are true or false. Let's solve each part step by step.

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Section A: Fill in the Blanks

#### Question 1:
"The presence of ________ in leaves indicates the occurrence of photosynthesis."

- Explanation: Photosynthesis is the process by which plants convert light energy into chemical energy. This process primarily occurs in the chloroplasts, which contain the pigment chlorophyll. Chlorophyll is essential for capturing light energy.
- Answer: Chlorophyll

#### Question 2:
"Substance that do not conduct heat are called ________."

- Explanation: Substances that do not conduct heat well are known as insulators. Examples include wood, plastic, and air.
- Answer: Insulators

#### Question 3:
"Temperature is measured in degree ________."

- Explanation: Temperature is commonly measured using the Celsius scale (°C), Fahrenheit scale (°F), or Kelvin scale (K). The most widely used scales in everyday life are Celsius and Fahrenheit.
- Answer: Celsius (or Fahrenheit/Kelvin, depending on context)

#### Question 4:
"Plants getting nutrition from dead and decaying matter are called ________."

- Explanation: Plants that obtain their nutrients from dead and decaying organic matter are known as saprophytes. These plants lack chlorophyll and rely on decomposing organic material for sustenance.
- Answer: Saprophytes

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Section B: Write True or False

#### Question 5:
"Heat energy flows from one body to another due to temperature difference between the two bodies."

- Explanation: Heat always flows from a region of higher temperature to a region of lower temperature. This is a fundamental principle of thermodynamics.
- Answer: True

#### Question 6:
"The fluid at the bottom of the pitcher plant contains digestive juices that digest the insects."

- Explanation: Pitcher plants are carnivorous plants that trap insects in their pitcher-shaped structures. The fluid at the bottom of the pitcher contains enzymes and bacteria that help break down the trapped insects, providing nutrients to the plant.
- Answer: True

#### Question 7:
"The clinical thermometer does not have a kink near the mercury bulb."

- Explanation: Clinical thermometers typically have a narrow constriction (kink) near the mercury bulb. This design prevents the mercury from flowing back into the bulb after it has been heated, allowing for accurate temperature readings.
- Answer: False

#### Question 8:
"Manures and fertilizers are used to replenish the nutrients in the soil."

- Explanation: Manures and fertilizers are added to the soil to provide essential nutrients (such as nitrogen, phosphorus, and potassium) that plants need for growth. This helps maintain soil fertility and supports healthy plant development.
- Answer: True

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Final Answers:

1. Chlorophyll
2. Insulators
3. Celsius (or Fahrenheit/Kelvin)
4. Saprophytes

5. True
6. True
7. False
8. True

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Boxed Final Answer:

\[
\boxed{
\begin{array}{ll}
1. & \text{Chlorophyll} \\
2. & \text{Insulators} \\
3. & \text{Celsius (or Fahrenheit/Kelvin)} \\
4. & \text{Saprophytes} \\
5. & \text{True} \\
6. & \text{True} \\
7. & \text{False} \\
8. & \text{True} \\
\end{array}
}
\]