In biology lab, you are observing and dissecting flatworms. Their bodies are very thin, even see-through, and their thin body surface allows them to exchange gases of oxygen and carbon dioxide with the underlying cells and tissues. Flatworms lack which of the following anatomical systems?
A. nervous
B. movement
C. respiratory
D. digestive
E. excretion
C. respiratory
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Which of the following types of blood vessels would have the greatest resistance to flow?
A. veins B. capillaries C. venules D. arteries E. arterioles
In addition to being a group of gram-negative bacteria considered normal flora of the gastroin-testinal tract of humans and animals, which one of the following also contains agents of impor-tant diseases such as gastroenteritis and enteric fevers, urinary tract infections, and bacterial pneumonia?
a. Neisseriaceae b. Micrococcaceae c. Enterococcus d. Enterobacteriaceae
The primary habitat for Vibrio spp. is:
a. freshwater. b. the upper respiratory tract of various mammals. c. brackish or marine water. d. the soil and water environment.
Which of the following is NOT a free-floating photosynthetic organism found in a lake?
A. phytoplankton B. green algae C. zooplankton D. cyanobacteria E. diatom