A student adds 100 g of liquid X to a solution Y in a beaker, places the beaker on a balance, and records the reading as 300 g. If the mass of the empty beaker is 50 g, what is the mass of solution Y in the beaker?

Which of the following policies is an example of a command-and-control policy? a. subsidies to education b. maximum levels of pollution that factories may emit c. tradable pollution permits d. none of the above is an example of a command-and-control policy.