Hi, 
I believe the answer is D, "Convival".
~Elisabeth
        
                    
             
        
        
        
The Olmecs were the first major civilization in Mexico following a progressive development in Soconusco. They lived in the tropical lowlands of south-central Mexico, in the present-day states of Veracruz and Tabasco. The natural <span>feature was important to the olmec people of san lorenzo are RIVERS. T</span><span>hey used rivers to travel between cities and build a strong trade system.</span>
        
             
        
        
        
This is another conservation of momentum problem.
the answer is 4.00m/s