Which of the following procedures describes the best method of obtaining the accurate mass of a sample in the laboratory? A. Zero the balance and then weigh the sample on the balance.

B. Use two different balances to weigh the sample and average the two weights together.

C. Check the balance for accuracy using a known weight weigh the sample three times on the balance, and use the average of the three masses.

D. Obtain the mass using a balance, remove the sample, re-zero or tare the balance and then weigh the sample a second time.

Cladistics is a way of classifying organisms by examining the characteristics of their ancestors and descendants and depicting the relationships in a cladogram. which of the following best describes a challenge in classifying organisms this way? a. there are millions of species on earth, and a cladogram is not a practical means for classifying all of them. b. it is impossible to tell which organisms are most closely related to each other using a cladogram. c. cladograms are detail-oriented and do not provide a useful understanding of evolutionary relationships. d. there is a limited number of ways to organize the information, so most cladograms end up looking very similar.

What might explain the real-world results, show in the graph to the right, for one class of twenty students? check all that apply.

Pwaves and s waves are alike in that they