Water flowing over fish gills exchanges gases with blood flowing in the opposite direction inside gill capillaries. This
is called __________. Fill in the blank(s) with the appropriate word(s).
ANSWER: countercurrent exchange
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A pharyngeal specimen is inoculated on cystine-tellurite blood agar, modified Tinsdale agar, and MacConkey agar. After 48 hours of incubation, black colonies with a brown halo are observed on the Tinsdale agar and gray colonies are isolated from the cystine-tellurite agar. However, no growth is observed on the MacConkey agar. Which one of the following statements explains this discrepancy?
a. The MacConkey agar is most likely ex-pired. b. The MacConkey agar should be incubated an additional 24 hours to observe growth. c. The pH of the media may be altered, causing an environment that is too acidic for the organism to grow. d. No discrepancy is present; this organism does not grow on MacConkey agar.
Amyloplasts are responsible for the colors of ripening fruits or autumn leaves
Indicate whether the statement is true or false.
A photograph formed using a microscope is called a(n) ____
a. spectrograph b. x-ray c. stereograph d. micrograph e. microphoto
One way RNA interference molecules work is by selectively cleaving DNA molecules that have sequences
complementary to small RNA molecules. _________________ Indicate whether the statement is true or false.