Question
A research was carried to determine the trend of growth of some boys and girls.Their average mass in kilograms was taken separately for a period of 20 years and tabulated as shown in the table below.
(a) On the same axis draw a graph of the average mass of the girls and boys against age.
(b) From the graph, determine the;-
(i) Mass of boys at the age of 11 years.
(ii) Growth rate of girls between ages 13 and 15.
(c) Account for the change in the mass of girls during the age stated in (ii) above.
(d) Explain the trend observed in the curves for both boys and girls.
(e) Why do girls above 10 years require in take of food that is richer in iron than boys of the same age?
(f) Part from using average mass to estimate growth in human beings, name two other parameters that can be used.
| Age | Average mass of boys (kg) | Average mass of girls (kg) |
|---|---|---|
| 0 | 2.5 | 2.5 |
| 2 | 11.5 | 11.5 |
| 4 | 15.0 | 16.0 |
| 6 | 18.5 | 19.3 |
| 8 | 22.1 | 27.1 |
| 10 | 25.1 | 27.1 |
| 12 | 27.5 | 30.5 |
| 14 | 37.0 | 35.5 |
| 16 | 44.0 | 44.0 |
| 18 | 46.9 | 52.0 |
| 20 | 48.5 | 55 |
(a) On the same axis draw a graph of the average mass of the girls and boys against age.
(b) From the graph, determine the;-
(i) Mass of boys at the age of 11 years.
(ii) Growth rate of girls between ages 13 and 15.
(c) Account for the change in the mass of girls during the age stated in (ii) above.
(d) Explain the trend observed in the curves for both boys and girls.
(e) Why do girls above 10 years require in take of food that is richer in iron than boys of the same age?
(f) Part from using average mass to estimate growth in human beings, name two other parameters that can be used.
Answer
(a)
(b)
(d) Girls generally grow faster than boys /boys grow slowly compared to girls but later after puberty they grow more steadily.
(e) Girls above ten years begin the menstruation cycle, they need more iron to replace the blood lost during menstruation
(f) Height of the body, volume of the body
(b)
(i) 26 kgs ±0.5
(ii) Girls 15 yrs - 39
Girls 13 yrs - 33/6
6 ÷ 2 = 3.0 kg/year
(d) Girls generally grow faster than boys /boys grow slowly compared to girls but later after puberty they grow more steadily.
(e) Girls above ten years begin the menstruation cycle, they need more iron to replace the blood lost during menstruation
(f) Height of the body, volume of the body
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