The echinoderm that differs from all others in that it lacks an endoskeleton, and only retains small bony pieces in its skin is the

(A) sand dollar

(B) sea lily

(C) brittle star

(D) sea cucumber

Which of these statements is false? a. others may notice a problem with a relationship before the people involved. b. the first sign of a problem with a relationship is a feeling of anger. c. damaged relationships can be repaired. d. even good relationships can be damaged.

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.

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.