<em><u>ANSWER</u></em>
ln most cases inorder to obtain the mass of a liquid one measures the mass of both the liquid and the container it is in and after wards remeasures the container alone and later subtract the mass of the container alone from the total mass of both the container and the liquid
+ not having enough food for everyone
+ how many people migrate
+ birth/death rates
+ how much water there is
+ how much nutrients/minerals are available
+ how much trees/oxygen is available
