If a storm breaks off the top of a tree, within a year or two, one of the lower branches will grow upward and become the new tree top, while inhibiting other branches from doing the same. This is an example of
A) the presence of cytokinins.
B) the influence of ethylene.
C) the formation of an abscission layer.
D) phytochrome inhibition.
E) apical dominance.
E
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What is the only group of Mollusca that does NOT have a radula?
A) Bivalves B) Gastropods C) Chitons D) Cephalopods E) All mollusk have a radula.
Through a microscope, paired chromosomes are visible within the nuclei of an unidentified cell sample. Which statement about these cells is true?
a. They cells have been damaged by prolonged dehydration and are beginning to die. b. The cells must be prokaryotes because eukaryotic nuclei are opaque to visible light. c. The cells were preparing to undergo cell division when the slide was prepared. d. The cells were collected from a patient suffering from acute celiac disease.
In Dianne Dodd's experiments with Drosophila pseudoobscura, different populations were established that were raised on diets of either maltose or starch
When flies from the different populations were allowed to mate, some flies mated with flies fed on a different food source, but there was a preference for mating with flies raised on the same food source. What does this phenomenon illustrate about the timescale of speciation?
The ________ have shells composed of calcium carbonate and thin pseudopods.
A. Amebozoa B. Euglenids C. Ciliates D. Dinoflagellates E. Foraminifera