The formula FG = mg relates an object's weight (FG) to its mass (m) and the acceleration due to gravity (g). The weight of an object is the force exerted on it by gravity and is measured in newtons (N). The mass of an object is a measure of its inertia, or the amount of matter it contains, and is measured in kilograms (kg). The acceleration due to gravity is a constant value that is approximately 9.8 m/s^2 on the surface of the Earth.
According to the formula, the weight of an object is directly proportional to its mass and the acceleration due to gravity. Therefore, if the mass of an object remains constant, any changes in its weight can only be caused by changes in the acceleration due to gravity.
For example, an object weighs 10 N on the surface of the Earth, but if you take it to a planet where the acceleration due to gravity is less, the weight of the object will decrease, even though its mass remains the same. The same applies to the opposite, If you take the same object to a planet where the acceleration due to gravity is higher, the weight of the object will increase, even though its mass remains the same.
In summary, the formula FG = mg shows that an object's weight is directly proportional to its mass and the acceleration due to gravity. If an object's mass remains constant, any changes in its weight can only be caused by changes in the acceleration due to gravity.