To what volume would i need to add water to the evaporated solution in problem 3 to get a solution with a concentration of 0.25 m?

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.

Burned piece of steel wool does not gain mass. so only d could be true.

Its not chemical its not radiation and its not convection because there is not movement of fluids so it is thermal conduction

The correct answer is:   [c]:     "it is the minimum amount of material needed to sustain a fission  reaction."