This map shows mexican climates. some of the best farmland is found in the north, where there is little rainfall. which of the following statements best explains how this is possible? a. winds carry adequate supplies of moisture from the nearby gulf of california.b. mexican farming does not require water.c. most crops today are grown on chinampas, or floating gardens.d. irrigation efforts have transformed dry land into farmland.

The correct answer is - D. Irrigation efforts have transformed dry land into farmland.

Naturally, the northern part of Mexico have been occupied by short and high grasslands, arid or semi-arid. These type of places actually manage to have very nice fertile soils with only a slight increase in the water they receive. As the irrigation methods have been developing, the rivers in the area have started to be used for irrigation purposes, and that gave the land just about enough amount of water. The grasses dispose very quickly, but are also very good natural fertilizer of the soil. The people started to produce more and more in the area, but also carefully managing the soil, and using the irrigation in a manner that will not cause erosion. Over time, parts of the north of the country managed to develop very good, fertile, highly productive farmlands.

81 is a composite number.