How were animals that were brought from the old world to the new world revolutionary for the new world? how did new world plants have a large impact on eurasia?

The Columbian Exchange brought lot of new animal species from the Old World to the New World, and lot of plants from the New World to the Old World, both of which had huge impacts.

The animals brought from the Old World to the New World, like the cows, horses, goats, sheep, poultry, all had big impact. Some were excellent for working on the farmlands, all of them were producing large amounts of excrement which was great for fertilization of the soil. Some were great for quick traveling, as well as being very useful in warfare. The majority of them provided food, be it meat, milk, or eggs, while some provided wool for clothing.

The plants brought from the New World to the Old World had huge positive impact in Eurasia as they managed to provide lot of food for the people, thus largely preventing malnutrition and famine. The most important of these plants is probably the potato, which has become one of the most valuable food sources, and one of the most popular as well.

the underground railroad (apocope of the metropolitan railroad) is a system of urban trains located within a city and its metropolitan area. it is characterized for being a massive transport of passengers in the big cities, uniting diverse zones and their environs, with high capacity and frequency and in segregated form to other systems of transport. metropolitan railroads are built underground or on the surface, although most systems use mixed models where sections are combined in both modalities.

1 - as a result, the metro tends to reduce car travel for two reasons: first, due to the greater transfer of users from the car and, second, due to the reduction in the acquisition of cars in homes located in sectors near the stations of the metro.

2 -the metro allows to contribute effectively to the achievement of all the objectives of an urban development policy: it improves the efficiency of the city's economy by reducing travel costs and also generates a higher level of activities in the city center, taking advantage of of the agglomeration economies.

3 -it is a clean means of transport, since it uses renewable energy (usually electricity), taking care of the environment and avoiding excessive pollution.

the answer would be c