When does a change in energy occur? 1. in some physical changes, but not all. 2. in every physical change, but not in a chemical change. 3. in every chemical or physical change.

3. in every chemical or physical change

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water

So what you would do is go through and add 3 teaspoons(tsp) 6 times because of the 6 tablespoons(tbsp). which will give you an answer of 18. another way is to multiply 3x6=18.