What was the primary motivation for the draining of lake beds in Mexico City?
A.
to reduce the risk of flooding
B.
to prevent the spread of diseases
C.
to protect the city from invaders
D.
to mine for gold under the lake beds

Please select the best answer from the choices provided.

A
B
C
D

ba geologist finds four sedimentary rock she determines that no geologic events have shifted the layers she labeles them a,b,c,dbfrom top to bottom

answer should be c..

the columbian exchange, also known as the columbian interchange, named for christopher columbus, was the widespread transfer of plants, animals, culture, human populations, technology, and ideas between the americas, west africa, and the old world in the 15th and 16th centuries, related to european colonization and trade following christopher columbus's 1492 voyage. invasive species, including communicable diseases, were a byproduct of the exchange. the changes in agriculture significantly altered and changed global populations. the most significant immediate impact of the columbian exchange was the cultural exchanges and the transfer of people between continents.

the new contact between the global population circulated a wide variety of crops and livestock, which supported increases in population in both hemispheres, although diseases initially caused precipitous declines in the numbers of indigenous peoples of the americas. traders returned to europe with maize, potatoes, and tomatoes, which became very important crops in europe by the 18th century.

the term was first used in 1972 by american historian alfred w. crosby in his environmental history book the columbian exchange. it was rapidly adopted by other historians and journalists and has become widely known.