A key trait that distinguishes gnathostomes from other chordate lineages is the presence of ____
a. bony scales
b. claspers
c. jaws
d. the operculum
e. keratin
ANSWER: c
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Mycorrhiza is a mutualistic relationship between ________
a. plant roots and fungi b. plant roots and bacteria c. green algae and fungi d. fungi and cyanobacteria e. cyanobacteria and zygomycetes
Cardiac muscle undergoes fast, synchronous contractions stimulated by ion flow. Which type of cellular junction is
essential for achieving this action in cardiac muscle?
a. gap junctions b. tight junctions c. plasmodesmata
d. adhering junctions e. desmosomes
Pairs of duplicated chromosomes produced during S phase are called ______
a. homologous chromosomes b. sister chromosomes c. sister chromatids d. heterologous chromosomes e. homogeneous chromosomes
How does S–Cdk help guarantee that replication occurs only once during each cell cycle?
(a) It blocks the rise of Cdc6 concentrations early in G1. (b) It phosphorylates and inactivates DNA helicase. (c) It phosphorylates the Cdc6 protein, marking it for destruction. (d) It promotes the assembly of a prereplicative complex.