Video Transcript
Many changes occur in the body
during puberty. In particular, growth rate
increases rapidly. The provided chart shows the growth
of a girl and a boy between the ages of two and 20. At what age did the girl most
likely start her puberty on the basis of the change in her growth? (A) Around 14, (B) around 11, (C)
around eight, or (D) around 15.
This question is asking us to use
the growth chart to identify the age at which the girl most likely started
puberty. The growth chart shows us how the
height of a girl and a boy changes as they increase in age. The question is asking us about the
girl, so we will only be referring to the pink line on the chart and can ignore the
blue line for the boy.
Let’s first establish what the
graph shows us about how the height of the girl changes as her age increases. As the 𝑦-axis indicates height and
the 𝑥-axis age, we can deduce that the steeper the line on the graph, the higher
the rate of growth. If we look at the pink line
indicating the height of the girl, we can see that between around 11 and 13 and a
half years of age, there is a period of rapid growth. The girl’s height increases from
around 125 centimeters to 157 centimeters during this time period.
You may recall that during puberty,
a growth spurt often occurs. A growth spurt is a rapid increase
in growth over a short period of time. The beginning of the growth spurt
is often a good indicator of the beginning of puberty in an individual. We have established that the growth
chart indicates the girl experiences a growth spurt from around 11 years of age. So this is also when she most
likely started her puberty.
We are now able to answer our
question. The correct answer choice is
(B). The age at which the girl most
likely started her puberty on the basis of the change in her growth is around
11.
