If an acid is added to a solution of a weak base and its salt,
a. more water forms, and more weak base ionizes.
b. the hydronium ion concentration decreases.
c. more hydroxide ions form.
d. more non-ionized weak base forms.

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. 

Decomposition is the cycle at which bacteria breaks down any organic material into the soil

Ithink b not to sure hope that : )

The answer is the third option extremely gradual