Final answer:
The aspect of 'neo-Malthusianism' that is most present in the colonial/classic approach, according to Blaikie, is population control and resource conservation. Neo-Malthusians, extending Malthus's theory, believe that overpopulation could lead to environmental collapse and conflicts over resources.
Step-by-step explanation:
According to Blaikie, the aspect of 'neo-Malthusianism' most clearly present in the colonial/classic approach is b) Population control and resource conservation. Neo-Malthusians build upon Thomas Malthus's original theory, focusing on the relationship between population growth and the earth's resources.
Thomas Malthus identified three factors that would limit human population growth: d) War, famine, and disease. Neo-Malthusians have expanded upon these ideas to suggest that overpopulation will lead not just to starvation but also to conflicts over scarce resources, such as food and the environment at large (Ehrlich 1968).
By comparison, the Cornucopian theory is more optimistic, with the belief that a) human ingenuity will solve any issues that overpopulation creates, contrary to the neo-Malthusian perspective, which emphasizes the need for population control to prevent environmental collapse and resource depletion.