Answer:
335 million years ago
Explanation:
Pangaea or Pangea ( /pænˈdʒiːə/) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and began to break apart about 175 million years ago.
 
        
             
        
        
        
1 the atmosphere because gas is everywhere. 
        
                    
             
        
        
        
San Francisco has an opportunity to reap tremendous economic, environmental, and health benefits by adopting recent advances in “green building”—benefits that will only increase in value over time. Many standard building design, construction, operation, and renovation practices are outmoded, inefficient, costly, and have adverse health and economic effects. The shift to new, environmentally sensitive practices would maintain San Francisco’s status as a leader in urban planning and environmental innovation. A shift to green buildings is also vital to enhancing San Francisco’s livability for its residents, workers, and visitors.
        
             
        
        
        
The air that is inside a ship is much less dense than water. That's what keeps it floating! ... As a ship is set in water, it pushes down and displaces an amount of water equal to its weight