Read the passage carefully and choose the best answer to each question out of the four alternatives. 

The use of work animals began long before humankind started to practice agriculture. The use of animal power is now considered by many people to be archaic and inefficient. Yet, despite the more than 50 years spent promoting tractorization in developing countries, the development gap between industrialized-countries and those with weak, highly dependent economies has increased. Moreover, the use of current production models, which are more critically dependent on fossil fuel, cannot be considered universally feasible. Alternative energy sources such as the effective use of work animals must urgently be established. Animals not only provide the means by which millions of families make a living, but they also contribute to ecologically and socially acceptable production systems. Moreover, the efficiency of their energy inputs into crop production is higher than that of machines. The rational use of work animals has the potential to contribute, specifically, to the living conditions and security of small-scale subsistence farmers.