Final answer:
The Atlantic Ocean is the major body of water that touches the northern shores of South America, with significant rivers like the Amazon and Orinoco flowing into it.
Step-by-step explanation:
The major body of water that touches the northern shores of South America is the Atlantic Ocean. This oceanic basin greatly influences the climate and geography of the continent. Large rivers like the Orinoco, the Sao Francisco, and the Paraguay and Paraná Rivers which flow into the Rio de la Plata, are key waterways that link the interiors of the continent to the Atlantic Ocean. Notably, the Amazon River, which sources from the Peruvian Andes, eventually drains into the Atlantic, thus profoundly affecting the economic and ecological landscape of the region.