A liquid sample has a reported volume of 810 mL. A. What is the implied +/- error of this measurement? And, identify the certain digits and the uncertain digits in the measurement. B. If the volume was instead able to be reported as 810. mL, what would be the implied +/-error? And, identify the certain and uncertain digits. C. Which of the two volumes 810 mL or 810. mL is more precise? What would have to change to allow the reported volume to be written as 810. mL instead of 810 mL?

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. 

Conservation efforts have been effective in "increasing the number of endangered species, reducing all the negative impacts of human activity, and preserving wildlife habitats".hope my answer has you : ) 

The answer is accuracy