If you move an object from the base of a mountain to the top of the mountain:

mass and weight remain constant
only mass remains constant
only weight remains constant
both mass and weight will change

The correct answer is: 'only mass remains constant

'.

Explanation;

Mass of an object is defined as a measure of the amount of matter contained in that object.It is usually measured in grams or in kilograms. It never changes in an situation, remains constant through the space.

Weight is defined as force exerted by the gravity on the object.It is measured in Newtons and calculated by using formula :

Weight= Mass × (Acceleration due to gravity) = mg

It is force which depends upon gravity.The value weight changes if the gravity varies.Hence, not a constant quantity.

From the given options the correct option is: 'only mass remains constant'.

increased stability in the completion of fluorine's outer shell.