What is the south american guarani aquifer system? 1.a 'no take' zone 2.a marine ecosystem 3.a supply of groundwater 4.the world's largest rain forest

The correct answer is 3. The South American Guarani Aquifer System is a supply of groundwater.

Explanation:

The Guarani Aquifer System is the largest underground reserve of freshwater in the world, occupying an area of approximately 1,200,000 km².  About 70% (840,000 km²) of the area occupied by the aquifer is located in the subsoil of center-southwest Brazil. The remaining is distributed between northeast of Argentina (255,000 km²), northwest of Uruguay (58,500 km²) and southeast of Paraguay (71,700 km²). The current population of the area of the aquifer is estimated at fifteen million inhabitants.

a characteristic is a deep cut in the earth or left over rock aka till.