Question

shaping a moist or wet sample of soil into a ball and rolling it into threads is called a ______ test
vibration
visual
plasticity
thumb

Explanation:

The test of shaping a moist or wet soil sample into a ball and rolling it into threads is related to the plastic behavior of soil, which is called the plasticity test. The other options: Vibration is not related to this manual shaping, Visual is just observation, and Thumb is a part of the process but not the name of the test.

Answer:

Plasticity (the option labeled "Plasticity")