NATO and the Warsaw Pact were examples of military alliances made for “collective security”. The correct option among all the options that are given in the question is the fourth option or option "D". The other choices are incorrect and can be easily negated. I hope that this is the answer that has helped you.
Answer:
Mass and density
Explanation:
Density of an object is defined as its mass per unit volume. Mathematically, the relation is given by :

m = mass and V = volume
If we know the density of the Eraser and its mass, we can easily find its volume. Hence, the two tools are mass and density.
This quote would most likely come out of a textbook that could be related to people who would support social darwinism. For that reason 3. Social Darwinism is the correct answer.
Social Darwinism talks exactly about this type of things where people and whole nations are in the struggle for survival and only the fittest ones will survive in this ongoing struggle.