In the planet Earth , there are movement like the plate tectonics , which makes the surface of earth crust to move continuously , which is capable to generate lines of individual islands and volcanoes .
But these type of tectonic movements are not possible in Venus or Mars .
Thereby making the surface of earth different from that of planet Mars and Venus .
Well to find this out you need to make an equation
s+7=j So for example if Johnny's sister is 15 then Johnny would be 22 because s(sister's age) +7(number of years difference between their ages)=22(Johnny's age)
