Which of the following statements is a weakness of using pheromones?
a. They are costly and time-consuming to produce.
b. They are more effective in the juvenile stage than the adult stage.
c. Insects develop resistance to pheromones.
d. They are biologically magnified in nontarget species.
e. They only work in large amounts.
A
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The charges with sodium chloride are all balanced-for every positive sodium ion, there is a corresponding negative chloride ion. Since its charges are balanced, how can sodium chloride be attracted to water, and vice versa?
A. This is not a matter of attraction. Sodium chloride dissolves in water because water provides a medium in which the individual sodium and chloride ions can disperse. B. Hydrogen bonding in water allows the sodium chloride molecule to be attracted to the water molecule. C. Dispersion forces come into play as the sodium chloride and water come into close proximity. D. As a water molecule gets close to the sodium chloride, it can distinguish the various ions and it is, thus, attracted to an individual ion by ion-dipole forces.
Almost all of the world's oceanic coastlines show evidence of ________ during the past 15,000 years
A) submergence B) emergence C) long-term stability D) isostasy E) heavy oil pollution
We calculate BSS = 10 * (540.3 - 543.6)2 + 16 * (602.9 - 543.6)2 + 17 * (489.8 - 543.6)2 = 105578.2 WSS = (10 - 1) * 46.42 + (16 - 1) * 47.42 + (17 - 1) * 48.92 = 91337.4 F = (BSS / (k-1)) / (WSS / (n-k)) = (105578.2 / (3 - 1)) / (91337.4 / (43 - 3)) = 23.1 The critical F value is F.05,2,40 = 3.23. The observed value vastly exceeds this, so we clearly reject the null hypothesis and conclude that the means differ across the groups.
In an energy diagram for an exothermic chemical reaction which of the following is true?
A) The energy of the products is lower than that of the reactants. B) The energy of the transition state is higher than that of the reactants. C) both a and b D) neither a nor b