Air masses are huge expanses of air that form from differential heating in the atmosphere. the boundary between two air masses is called a weather front. fronts can create particular types of weather. identify each front by the weather it produces.

4,560 pounds of soil

Step-by-step explanation:

Ok, based on the information given we are assuming that Persephone's garden is in the shape of a square or rectangle and the measurements 8 by 19 are in feet. That being the case we first need to calculate the square footage of the garden and we do this by multiplying the length by the width like so...

8 ft * 19 ft = 152 sq. ft.

Now that we know the square footage, we calculate how much soil is needed. Since the question states that she needs 30 pounds of soil per square foot then we multiply the square footage of the garden by 30.

152 sq. ft. * 30lb =  4,560lb

Finally, we can see that Persephone will need 4,560 pounds of soil for her garden.