Approximately how much water does Earth's hydrosphere contain?

Which technically is nasa developing that will astronauts reach mars

The shift of a vehicle's weight around its center of gravity is known as

Ricardo notices that when he plays soccer in the rain, his ball does not seem to go as far after a kick. what is the best scientific question that ricardo could ask about this observation? is soccer better played in the rain or sun? how does rain affect the distance a soccer ball can travel? how does rain affect the speed of a soccer ball? is soccer affected by the rain?