Question

gizmo warm - up
if you stand by the bank of a river, it may seem that very little is
happening. but over thousands and even millions of years,
rivers can have a profound effect on the landscape. in the river
erosion gizmo, you will see how rivers move materials and how
they affect landscapes.
to begin, check that mountain river and short - term erosion are selected. the gizmo shows a
typical river that is moving through a hilly area.

1. the two movie cameras ( ) allow you to observe different parts of the river up close. click

on the left movie camera. what do you see?

1. sediments are small rock fragments such as sand or pebbles. what evidence do you see

that sediments are being transported?

1. now select the right movie camera to see the bank of the mountain river. what is happening

to sediments on the bank?

Explanation:

This problem is about river erosion and sediment transport, which falls under the subfield of Geography (Natural Science). However, since the questions are about observations in a Gizmo simulation, the answers would be based on typical river erosion simulation observations. For question 1, clicking the left movie camera (usually showing the river channel) would show water flowing, possibly with sediments moving. For question 2, evidence of sediment transport could be seeing particles like sand/pebbles moving with the water current. For question 3, on the river bank, sediments might be deposited (settling out) or eroded (being picked up by water), but in a mountain river bank, often erosion of sediments from the bank or deposition as the water slows near the bank. But since this is a simulation - specific question, the exact answers depend on the Gizmo's visual output. However, for the purpose of answering the subfield, it's Geography (Natural Science).

Answer:

The subfield is Geography (under Natural Science). For the questions:

1. (Typical observation) Water flowing rapidly, possibly carrying small rock fragments (sediments).
2. (Typical evidence) Sediments (like sand, pebbles) are visible moving along with the river's current.
3. (Typical observation) Sediments on the bank may be eroded (being carried away by the river) or deposited (settling as the water near the bank slows down).