I have a question about a practice test!! Why is the correct answer is A? I chose B.

Question

Historically, as countries have developed industrially, they have undergone declines in death rates followed by declines in birth rates. Over time they have tended to move from rapid increases in population to slower increases, then to zero growth and finally to population decreases. The model which demographers use to help explain these changes in population growth is known as the demographic transition model. In order to properly appreciate the demographic transition model, it is necessary to understand two basic concepts: the crude birth rate(CBR)and the crude death rate(CDR)The CDR is determined by taking the number of births in a contrary in a given year and dividing it by the total population of the country and then multiplying the answer by one thousand. So, for example, the CBR of the United States in 2004 was 14(in other words there were 14 births per thousand living people in that year). CDR is worked out in a similar way. The CDR for the United States in 2004 was 8 per thousand. 

2, According to paragraph 1, what is useful about the demographic transition model?

A, It helps explain trends in population growth over time.

B, It can be used to measure birth and death rates.

C, It clarifies the causes of population increase.

D, It predicts the relative speed of population patterns.

Answer 1

Hi Saori,

 

   According to the information in the paragraph,  demographic transition model or  DTM accounts for  crude death rates/CDR and  crude birth rates/CBR in a given population in a precise period of time. The data from CDR and CBR are used to explain the observed trend of population growth in the defined population. DTM can be used to measure CDR and CBR in a given population, however, its real function is to explain the trend in the pattern of population growth over the time. Therefore, A is correct since it includes that information and B is incorrect as it excludes that information .

 

Similarly  DTM does not completely clarify the causes of population increase as it does not account  for immigration and therefore,  C is incorrect.

 

DTM cannot predict the  speed of population pattern and therefore, D is incorrect as well.

 

Hope this helps.