Some species of rotifers undergo parthenogenesis, which means that __________.

Leeches are members of the phylum __________ in the clade of bilaterally symmetric animals called __________.

Tapeworms are highly specialized worms that make their living as endoparasites. To which of the following phyla do the tapeworms belong?

The proglottids of a tapeworm contain an elaborate __________ system.

Which of the following groups of worms is/are completely parasitic?

A land snail, a clam, and an octopus all sharea. a mantle.b. a radula.c. gills.d. distinct cephalization.

The genes for the traits that Mendel worked with are either all located on different chromosomes or behave as if they were. How did this help Mendel recognize the principle of independent assortment?a. Otherwise, his dihybrid crosses would not have produced a 9 : 3 : 3 : 1 ratio of F2 phenotypes.b. The occurrence of individuals with unexpected phenotypes led him to the discovery of recombination.c. It led him to the realization that the behavior of chromosomes during meiosis explained his results.d. It meant that the alleles involved were either dominant or recessive, which gave 3 : 1 ratios in the F1 generation.

What is a lophophore?a. a specialized filter-feeding structureb. the single opening in species with a blind gutc. a distinctive type of larva with a band of ciliad. a synapomorphy that defines lophotrochozoans

Brachiopoda is a phylum within the Lophotrochozoa. Even though they are not closely related to bivalve mollusks (such as clams or mussels), brachiopods look and act like bivalve mollusks. Specifically, brachiopods suspension feed, secrete calcium carbonate shells with two valves that hinge together in some species, and attach to rocks or other hard surfaces on the ocean floor. How is it possible for brachiopods and bivalves to be so similar if they did not share a recent common ancestor?