Plasmodesmata are
a. only found in root cells.
b. connections between xylem and phloem.
c. incapable of structural change.
d. able to be opened and closed.
e. only found in leaf cells.
D
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Which of the following choices is an example of a positive feedback mechanism?
a. ceasing exercise when tired b. sweating when hot c. contractions in childbirth increasing production of oxytocin d. eating when hungry and stopping when full
Which of the following is a protozoan with two nuclei and no mitochondria?
A) Plasmodium B) Paramecium C) Euglena D) Giardia E) Trichomonas
If the decision to include average tenure at the company as a control variable in an attempt to estimate if West coast store locations are outperforming store locations in the rest of the country (i.e., the regression, StoreProfitsi = ?0 + ?1West Coasti + ?2Avg.Tenurei + Ui), which of the following conditions need to be true in order for the estimate of ?1 to be the same regardless of whether Avg. Tenure is used as a control or not?
A. The semi-partial correlation of Store Profits on West Coast holding Avg. Tenure fixed is zero. B. The p-value on average tenure is above 0.10 C. Average tenure and West Coast are uncorrelated. D. The p-value on average tenure is low.
Exotoxins are
A. secretions that always target nervous tissue. B. antiphagocytic factors. C. lipopolysaccharides. D. only released after a cell is damaged or lysed. E. proteins.