A student made a model of a river in a sandbox. A pile of
sand represents soil and bits of rock in the riverbed. Water
pouring from a hose represents river water as it flows
downhill.
Which two characteristics are limitations of the student's
model?
A. The model is much smaller than a real river.
B. The model is missing plants, fish, and other details
found in a real river.
C. The model soil is nothing like the soil found in a real
riverbed.
D. The model river water flows downhill instead of
uphill like real river water does.