In the mid-twentieth century and corroborated ever since, researchers dredging the seafloor could not find any materials older than 180 million years.
<h3>
What do you understand by seafloor ?</h3>
The surface of an ocean or sea: seafloor According to this theory, the Earth's crust is divided into a number of enormous plates that together form the continents and ocean floors and are supported by a warm, plastic "mantle" beneath the surface. Mr. Walter Sullivan
Deposits of common minerals like copper, zinc, nickel, gold, silver, and phosphorus can be found on the seafloor. These deposits are nodules on silt from the abyssal plain that are typically 3 to 10 centimeters (1 to 4 inches) in diameter and appear as crusts on volcanic and other rocks.
To learn more about the seafloor, Visit: 
brainly.com/question/1327852
#SPJ4
 
        
             
        
        
        
“One thing that is poorly understood is population growth in Africa,” says William Cobbett, director of Cities Alliance . “It is thought that populations are growing mainly because of urban migration. That’s not correct. Across the continent, the bulk of population growth comes from natural population growth. Undesa figures from 1950-2050 show that in the case of Uganda – the outlier – its population in one century will multiply 20 times. That has never happened in human history.” Tanzania will grow 18 times and Nigeria 10.5.
“Most local authorities don’t have the capacity to deal with this, so there is no forward planning to make provisions for this population growth, which we know is going to happen.”
His organisation is trying to combat the mindset that you can’t plan for increased slum population, by supporting the creation of municipal development forums in a number of Ugandan cities. These are structured discussions where the local authority, local private sector companies and slum dwellers meet and deliberate about the future of the city.
Having the capacity to plan for future slum populations isn’t just a problem limited to Africa though.
        
             
        
        
        
Answer:
Carves landscapes from below the surface 
Explanation:
Groundwater is below the surface, and using the process of elimination, you will be left with the first choice, carves landscapes from BELOW the surface. 
 
        
             
        
        
        
Guangzhou 113°E 23°N
shanghai 121°E 31°N
so the direction is northeast
        
             
        
        
        
The answer is subtropical