1. the enzyme dna polymerase works
only in the 5' to 3' direction. how does this
affect the leading strand and the lagging
strand?
c) a. dna polymerase can use only the
leading strand as a template. a different
enzyme is used to synthesize dna on the
lagging strand.
c) b. dna polymerase can work
continuously on the leading strand but works
discontinuously on the lagging strand,
creating okazaki fragments.
c) c. dna polymerase can work
continuously on the leading strand but must
flip the lagging strand around before it can
work on it.
a n nma " aa.“ , a.“ ira“.

At the complete end of cellular respiration, how many molecules of atp are produced?               a.  15    b.  26    c.  38    d.  34 

Put the following steps of the convection process in the correct order. 1. gravity pulls cooler matter downward. 2. the matter expands and decreases in density. 3. an up-and-down flow of matter produces a convection current. 4. matter is heated. 5. warmed matter is forced upward. question 2 options: a) 4, 2, 5, 1, 3 b) 2, 4, 3, 1, 5 c) 3, 2, 5, 4, 1 d) 1, 4, 2, 5, 3

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.