The proglottids of a tapeworm contain an elaborate __________ system.

During typical earthworm reproduction, __________.

Annelids __________.

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?

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

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

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.