Describe the three types of system: a. open: b. closed: c. isolated:

An open system is when there is a transfer of energy and matter with its surroundings.

A closed system is where there is a transfer of energy, may it be heat or work, but not matter with its surroundings.

An isolated system is where there is no transfer of energy or matter with its surroundings.

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant. 

60.0 - there are 3 significant numbers