Sentence:  The number of adult rabbit pairs being present in consecutive months is then given by the <WSD>Fibonacci sequence</WSD>: 1, 1, 2, 3, 5, 8, 13, 21, ... (every term is the sum of its two predecessors). This work can be seen as the very beginning of mathematical biology, though one has to admit that the <WSD>Fibonacci sequence</WSD> exerts a greater fascination for number theorists than for reproductive biologists. 
Meaning of the word marked with <WSD> tags:  The sequence of integers, each of which is the sum of the preceding two, the first and second numbers both being 1.