In a large lecture class, a professor decides to make his class notes available on the Internet. During one of his lectures, he mentions that he would like some feedback concerning the usefulness of these notes. He asks students to leave written comments in his mailbox regarding the usefulness of having the class notes available on the Internet. He gets written comments from twenty-three students, and, in their written comments, most indicate that having the notes readily available helped them in the course. This is an example of

a voluntary response sample.

Explanation:

A voluntary response sample is described as a type of sample made up for participants to give their review on a subject matter. The purpose of a voluntary response sample is for the researcher to see the reviews of the people he or she is sharing the information with. This is the scenario between the professor and his students, he wants to know their view as regards him posting the notes online for them.

the correct answer is 2.

a slump in geology means a mass movement process of slope failure. a mass of rock or unconsolidated material drops along a slip surface. in other words, rock layers move a short distance down the slope. the slump block is an intact block (2), without any landslide material.

in this image, 1 is the surface of rapture (scarp), 2 the slump block, 3 main scarp (crown), 4 base of rapture with debris flow.

slumps are caused by clear cutting on unstable soils and the sagging of earth, in coastal areas they are due to wave infiltration.