PLSS HELP What is the relationship of pulling with energy?

1.Energy causes pulling to happen with more force.
2.Only potential energy works on pulling.
3.Energy allows objects to move.
4.In order to pull an object it requires energy.

Density= mass/volume so 5.1 divided by 4.7 is  5.1 / 4.7 =1.08510638298round to the correct number of sig figs

Ithink the answer is c

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.