Differentiate between primary and secondary growth in plants. Be sure to include the results of each and where each
type of growth would be most likely to occur. What will be an ideal response?
Primary growth refers to growth in stem and root length. This vertical growth occurs only at
the root and shoot tips, specifically at the root and shoot apical meristems. Primary growth
results in the formation of primary tissues, such as primary xylem, primary phloem,
parenchyma, collenchyma, and sclerenchyma. Secondary growth refers to lateral growth; i.e.,
secondary growth results in an increase in the girth of the plant. Secondary growth results
from the activity of lateral meristems, which in term produce secondary tissues: the vascular
cambium produces secondary xylem and secondary phloem, and the cork cambium produces
cork parenchyma and cork cells. These last three tissues comprise the periderm which
replaces the epidermis in woody plants.
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The difference between a society and an aggregation is that aggregations are characterized by:
a. communication between all animals present. b. individuals present only for breeding. c. a lack of intentional interaction between those animals present. d. confinement; while in a society the individuals are free to enter and exit. e. genetically determined behavioral responses required to bring these individuals together.
During S phase, each chromatid is copied, forming
What will be an ideal response?
The modification of the DNA of an organism to produce new genes with new traits is most properlycalled:a
bioengineering. b. in vitro gene technology. c. biotechnology. d. recombinant DNA technology. e. genetic engineering.
The figure above illustrates antibody titers produced during a primary and secondary immune response. All of the following statements about the primary and secondary immune response are correct EXCEPT which one?
A) Antibody is produced at a much higher rate during the secondary immune response. B) The antibody level produced in the secondary response is three times greater than that produced during the primary immune response. C) There is a lag time between antigen exposure and antibody production in the primary immune response that is not seen in the secondary immune response. D) The difference between the two responses is due to the presence of memory cells during the secondary response. E) Antibody levels stay elevated for a longer time following a secondary response.