Free WJEC GCSE Combined Science (3430) Exam Questions and Answers

Plant leaves absorb light for photosynthesis. State the source of the light absorbed by the leaves.

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Image 1.1 shows a violet plant (Viola riviniana). Gareth calculated the area of a leaf from one of the violet plants. This is what he did: Step 1. He drew an outline of a leaf on a grid as shown in Image 1.2. Step 2. He counted the number of whole squares inside the outline. Step 3. He multiplied the total number of whole squares by the area of one square. Count the number of whole squares inside the outline. Number of whole squares inside the outline = ____

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Image 1.1 shows a violet plant (Viola riviniana). Gareth calculated the area of a leaf from one of the violet plants. This is what he did: Step 1. He drew an outline of a leaf on a grid as shown in Image 1.2. Step 2. He counted the number of whole squares inside the outline. Step 3. He multiplied the total number of whole squares by the area of one square. Each square has an area of 0.25 cm². Use the formula below to calculate the outline area. Outline area = 0.25 × number of whole squares inside the outline. Outline area = ____ cm²

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Image 1.1 shows a violet plant (Viola riviniana). Gareth calculated the area of a leaf from one of the violet plants. This is what he did: Step 1. He drew an outline of a leaf on a grid as shown in Image 1.2. Step 2. He counted the number of whole squares inside the outline. Step 3. He multiplied the total number of whole squares by the area of one square. Counting only the whole squares gave an outline area which was much lower than the actual leaf area. Explain why.

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Image 1.1 shows a violet plant (Viola riviniana). Gareth calculated the area of a leaf from one of the violet plants. This is what he did: Step 1. He drew an outline of a leaf on a grid as shown in Image 1.2. Step 2. He counted the number of whole squares inside the outline. Step 3. He multiplied the total number of whole squares by the area of one square. Suggest one improvement to step 2 to get an answer closer to the true value.

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Gareth decided to test the following hypothesis: “The leaf area of violet plants in the shade will be greater than that of violet plants in bright light”. He picked one violet plant growing in shade and one growing in bright light. Gareth used his method to calculate the leaf areas of 10 leaves from each plant. The mean results are shown in Table 1.3. Table 1.3 | Plant growing in | Mean leaf area (cm²) | | shade | 1.5 | | bright light | 0.9 | Calculate the difference in mean leaf area between the two plants. Difference = ____ cm²

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Gareth decided to test the following hypothesis: “The leaf area of violet plants in the shade will be greater than that of violet plants in bright light”. He picked one violet plant growing in shade and one growing in bright light. Gareth used his method to calculate the leaf areas of 10 leaves from each plant. The mean results are shown in Table 1.3. Table 1.3 | Plant growing in | Mean leaf area (cm²) | | shade | 1.5 | | bright light | 0.9 | Complete the following sentence by underlining the correct word. The results show that Gareth’s hypothesis is: invalid / rejected / supported.

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Explain the advantage of a large leaf area for plants growing in shade.

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Image 2.1 shows the digestive system. Some structures have been labelled. Complete the following sentences by underlining the correct word. Peristalsis in the digestive system causes food to be digested / moved / absorbed.

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Image 2.1 shows the digestive system. Some structures have been labelled. One organ where peristalsis happens is the gall bladder / oesophagus / pancreas.

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