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Birth defects in humans can be caused by chromosomal abnormalities - HSC - SSCE Biology - Question 24 - 2022 - Paper 1
Question 24
Birth defects in humans can be caused by chromosomal abnormalities. | Maternal age | Prevalence of chromosomal abnormalities | | (years) | (per 1000 births) ... show full transcript
Worked Solution & Example Answer:Birth defects in humans can be caused by chromosomal abnormalities - HSC - SSCE Biology - Question 24 - 2022 - Paper 1
Step 1
Draw a suitable graph of the data provided in the table.
Answer
To create the graph:
- Label the Axes: The x-axis represents 'Maternal age (years)' and the y-axis represents 'Prevalence of chromosomal abnormalities (per 1000 births)'.
- Scale the Axes: For the x-axis (Maternal age), use a range from 20 to 45 years. For the y-axis (Prevalence), scale it from 0 to 40, ensuring intervals are consistent and readable.
- Plot the Data Points: Mark the points corresponding to the data in the table:
- (20, 1.5)
- (30, 3)
- (35, 8)
- (40, 22)
- (45, 38)
- Draw the Line of Best Fit: Connect the plotted points with a smooth curve that best represents the trend of increase in prevalence with maternal age.
Step 2
Outline the main features of the trend.
Answer
The graph indicates a clear positive correlation between maternal age and the prevalence of chromosomal abnormalities. Notably, as maternal age increases, the prevalence also increases. After age 30, this increase becomes more pronounced, showing a steep rise, particularly after 40 years.