The olmec people..

constructed giant stone monuments.

built pyramids out of blocks of stone.

developed a writing system with pictographs.

created a system of numbers that included zero.

The correct answer for above statement is:

A) constructed giant stone monuments.

Explanation:

The Olmec were the first important civilization in Mexico. They existed in the tropical marshes on the Gulf of Mexico in the present-day Mexican states of Veracruz and Tabasco. The name Olmec is a Nahuatl the Aztec language word,it means the rubber people. The Olmec people created giant stone monuments. developed a writing.

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.