Many people never even taste butter, instead use oleo or margerine...fake stuff. Real butter is the best topping for popcorn! And crab legs are good dipped in it, as well as hot corn on the cobb. This is how I eat butter.
Answer:
System D --> System C --> System A --> System B
Explanation:
The gravitational force between two masses m1, m2 separated by a distance r is given by:

where G is the gravitational constant. Let's apply this formula to each case now to calculate the relative force for each system:
System A has masses m and m separated by a distance r:

system B has masses m and 2m separated by a distance 2r:

system C has masses 2m and 3m separated by a distance 2r:

system D has masses 4m and 5m separated by a distance 3r:

Now, by looking at the 4 different forces, we can rank them from the greatest to the smallest force, and we find:
System D --> System C --> System A --> System B
Its b i literally have had this exact question
Density is the mass of a substance per unit volume.