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IELTS Practice Reading: Label Diagram ID: #56219 Hard Nature Works PLA
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The basic raw materials for PLA are carbon dioxide and water. Growing plants, like com, take these building blocks from the atmosphere and the soil. They are combined in the plant to make carbohydrates (sucrose and starch) through a process driven by photosynthesis. The process for making Nature Works PLA begins when a renewable resource such as corn is milled, separating starch from the raw material. Unrefined dextrose, in turn, is processed from the starch.

Cargill Dow turns the unrefined dextrose into lactic acid using a fermentation process similar to that used by beer and wine producers. This is the same lactic acid that is used as a food additive and is found in muscle tissue in the human body. Through a special condensation process, a lactide is formed. This lactide is purified through vacuum distillation and becomes a polymer (the base for NatureWorks PLA that is ready for use through a solvent-free melt process. Development of this new technology allows the company to “harvest” the carbon that living plants remove from the air through photosynthesis. Carbon is stored in plant starches, which can be broken down into natural plant sugars. The carbon and other elements in these natural sugars are then used to make NatureWorks PLA.

4 labels
Diagram
Options:
distillation
condensation
photosynthesis
starch
carbon dioxide
fermentation
dextrose
polymer
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AI explanationShows the answer. Tap to open.

Question Focus: The diagram shows an early stage where a plant material is processed and something is separated out. We need to identify what is separated from the raw material.

Correct Answer: D

Why this is correct: The diagram is showing the milling stage. The passage clearly says the resource is milled, separating starch from the raw material. So the correct label here is starch.

Passage Reference: The process for making Nature Works PLA begins when a renewable resource such as corn is milled, separating starch from the raw material.

Common Mistake: Some students choose dextrose because it appears soon after. But dextrose is made later from starch, not separated at this stage. This is a sequence trap.

Paraphrasing: Passage: 'separating starch from the raw material' = Diagram: '___ is separated from the raw material'

Tips: When a diagram shows the first steps, match it to the earliest process sentence in the passage.

Key Vocabulary:

  • milled = ground into smaller pieces
  • raw material = basic natural material

Question Focus: The diagram shows the step where dextrose is changed into lactic acid. We need the name of this process.

Correct Answer: F

Passage Reference: Cargill Dow turns the unrefined dextrose into lactic acid using a fermentation process similar to that used by beer and wine producers.

Why this is correct: The diagram shows dextrose being transformed into lactic acid. The passage says this happens using a fermentation process. So the correct answer is fermentation.

Common Mistake: A common wrong choice is condensation because it sounds technical. But condensation happens later, after lactic acid is formed. This is a wrong section trap.

Paraphrasing: Passage: 'turns the unrefined dextrose into lactic acid using a fermentation process' = Diagram: 'dextrose is changed by ___'

Tips: If the diagram shows a change from one substance to another, look for verbs like turn into or change into in the passage.

Key Vocabulary:

  • fermentation = chemical change using natural processes
  • unrefined = not fully cleaned or purified

Question Focus: The diagram shows what happens after lactic acid is produced and before purification. We need the process name.

Correct Answer: B

Passage Reference: Through a special condensation process, a lactide is formed.

Why this is correct: After lactic acid is made, the passage says through a special condensation process, a lactide is formed. That matches this diagram step exactly, so the answer is condensation.

Common Mistake: Some students choose distillation because purification is mentioned nearby. But distillation happens after condensation, not before. This is a sequence trap.

Paraphrasing: Passage: 'Through a special condensation process, a lactide is formed' = Diagram: 'lactic acid is processed by ___'

Tips: Always check what comes before and after a step. Diagrams usually follow the same order as the passage.

Key Vocabulary:

  • condensation = process of combining substances
  • formed = created

Question Focus: The diagram shows the final product that is ready for use. We need to label what the purified material becomes.

Correct Answer: H

Passage Reference: This lactide is purified through vacuum distillation and becomes a polymer (the base for NatureWorks PLA that is ready for use through a solvent-free melt process.

Why this is correct: At the final stage, the passage explains that the purified lactide becomes a polymer and is ready for use. That matches the last box in the diagram, so the answer is polymer.

Common Mistake: Students sometimes pick distillation because purification is mentioned. But the diagram asks for the result, not the method. This is a context shift trap.

Paraphrasing: Passage: 'becomes a polymer that is ready for use' = Diagram: 'final product: ___'

Tips: For the last box in a process diagram, look for phrases like final, ready for use, or becomes.

Key Vocabulary:

  • polymer = large material made of many small units
  • purified = cleaned

General Tips:

  • Diagram questions usually follow the passage order. Use the previous answer to help you find the next one.
  • Focus on what the diagram box is asking for. Is it a material or a process?
  • Do not choose a word just because it sounds scientific. Check the exact stage carefully.
  • Cross out options as you use them so you do not reuse the same word.

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