Individuals that are heavy smokers may eventually have trouble clearing the mucous from their lungs because the structures that move fluid along the epithelial lining of the lung become damaged over time. What are these structures called?
A. Pili
B. Flagella
C. Cell walls
D. Cilia
D. Cilia
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The common ancestor of the protostomes had a coelom. What does this suggest?
A) All lophotrochozoans have a coelom. B) There are no pseudocoelomates within the protostomes. C) There are no acoelomates within the protostomes. D) The body cavity evolved before the lophophore.
Which muscles contract during a restful expiration?
a. external intercostals. b. diaphragm. c. abdominal. d. both b and c.
Plants are:
a. multicellular, prokaryotes, autotrophs b. unicellular, eukaryotes, autotrophs c. multicellular, eukaryotes, autotrophs d. multicellular, eukaryotes, heterotrophs
An advantage of a complete digestive system over a gastrovascular cavity is that the complete system _____
A) excludes the need for extracellular digestion B) allows for specialized regions with specialized functions C) allows extensive branching D) facilitates intracellular digestion