The Crusades were military expeditions undertaken by a. european christians who wanted to destroy constantinople
b. muslim armies who sought to conquer Europe
c. European Christians to regain the Holy Land from the Muslims
d. Christian and Muslim armies who joined to fight the Mongols

European Christians to regain the Holy Land from the Muslims

Explanation:

The "crusades" were, indeed, military expeditions managed by the European Christians. Its main purpose was to recover the "Holy Land," the area situated between the Mediterranean Sea and the Jordan River. It was under the Islamic rule that was brought about by Muslim expansion.

Many participants volunteered because this was also viewed as a way of removing one's sin and renewing spiritual relationship with God.

1st amendment: freedom of speech, religion, petition, press, and assembly

2nd: right to bear arms

3rd: quartering of soldiers

4th: search and seizure

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.