Explanation:

- Let's start with the statement that introduces the topic. Sentence C does this by defining the "growth of population."

- Next, Sentence B logically follows by explaining that this change can be expressed in two ways.

- Sentence D naturally follows B, detailing what those two ways are: absolute numbers and percentage change.

- Sentence A is best placed at the end, adding another aspect, the rate of population increase, to consider.

Correct Order: CBDA

- Option 2: CBDA

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In summary, option 2 organizes the sentences in a coherent logical flow, thoroughly discussing population growth and its measurement before introducing the concept of rate.