What three conditions must be satisfied for a scientific theory to be valid

layer a is the exosphere and layer b is the thermosphere.   is the answer i think but i hope this .

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.

conservation of mass

mass before something happens = mass afterwards