Which of the following is a good soil conservation method to reduce the loss of topsoil
on gentle slopes that are farmed?
A) Planting crops parallel to the contours of the slope.
B) Leaving crop residues (i.e., stalks) in place in the field.
C) Planting grass in natural drainageways on the slope.
D) All of these choices are good for soil conservation.
What combination of factors was responsible for the disaster west of Yellowstone
National Park on August 17, 1959?
A) Rock falls filled a lake with debris until the water overtopped the dam and eroded
through the concrete.
B) Water migrating along foliation layers in the metamorphic rock destabilized a dam,
which collapsed and flooded the valley.
C) A severe earthquake triggered a slide that blocked a river and flooded a campground.
D) Drainage from the reservoir generated a lahar, which destroyed small towns
downstream.