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Figure 5 (i) An optician tested the eyesight of 240 people - Edexcel - GCSE Biology - Question 4 - 2023 - Paper 1
Question 4
Figure 5 (i) An optician tested the eyesight of 240 people. 35% of these people could read the normal vision row without wearing glasses. Calculate the number of pe... show full transcript
Worked Solution & Example Answer:Figure 5 (i) An optician tested the eyesight of 240 people - Edexcel - GCSE Biology - Question 4 - 2023 - Paper 1
Step 1
35% of these people could read the normal vision row without wearing glasses.
Answer
To calculate the number of people who need glasses, first determine how many could read without glasses:
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Calculate 35% of 240:
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Now, subtract this number from the total to find how many need glasses:
Thus, 156 people need glasses to correct their vision.
Step 2
Which diagram shows how short-sightedness can be corrected?
Answer
To answer this part, select the diagram that represents the use of diverging lenses, which helps in correcting short-sightedness. Typically, this would be Diagram A, as it shows rays of light being refracted outward (diverging) before entering the eye.
Step 3
Describe why a person with cataracts would see the image shown in Figure 6.
Answer
A person with cataracts experiences clouding of the lens in the eye, which obstructs light from passing through clearly. This results in blurry vision, distorted images, and difficulties with night vision.
The lens may be too thick or cloudy, which further prevents light from focusing properly on the retina, causing images to appear unclear.
Step 4
Step 5
Describe how messages are sent from the brain to muscles.
Answer
Messages are sent from the brain to muscles through motor neurons. When the brain decides to initiate a movement, it sends electrical impulses down the spinal cord and out through the motor neurons. These neurons release neurotransmitters at the neuromuscular junction, which bind to receptors on muscle fibers, causing them to contract and produce movement.