eaf82217_ehension__An_exploratory_study__Extract_1b
[Extract 1a] In the animal and vegetable world the growth of numbers is governed by the tendency of individuals to propagate their species on the one hand, and on the other hand by the struggle for life which thins out vast numbers of the young before they arrive at maturity. In the human race alone the conflict of these two opposing forces is complicated by other influences. On the one hand, regard for the future induces many individuals to control their natural impulses; sometimes with the purpose of worthily discharging their duties as parents; sometimes as for instance at Rome under the Empire, for mean motives. [Extract 1b] 
In the animal and vegetable world the growth of numbers is governed simply by the tendency of individuals to propagate their species on the one hand, and on the other hand by the struggle for life which thins out vast numbers of the young before they arrive at maturity. In the human race alone the conflict of these two opposing forces is complicated by the influences of forethought and self control, of prudence and a sense of duty.
Reading in a Foreign Language: Metadiscourse and ESP reading comprehension: An exploratory study
Extract 1b