Question

a second group of researchers designed a second experiment that examined the distribution of newt ttx production and ttx resistance in snakes at a site in alaska during the 20 years after snakes had colonized the region. these results are shown in the table below.

year	percent of newts producing detectable ttx	mean ttx production (mg)	percent of snakes with ttx resistance	mean ttx resistance among resistant snakes (mg)
5	96.4	0.29	32.7	0.112
10	99.7	0.34	68.4	0.291
20	100.0	0.35	97.2	0.876

based on the data above, a researcher hypothesizes that an increase in the frequency of ttx-producing newts contributes to an increase in the frequency of ttx-resistant snakes and promotes adaptations in snakes beyond the level of the threat posed by newts. what evidence from each experiment best support this argument?

a. | experiment 1 | experiment 2 |

the level of ttx produced by newts in areas where snakes exhibit a resistance greater than 10 mg ttx

the increase in the percent of ttx-producing newts and ttx-resistant snakes at the alaskan site over time

b. | experiment 1 | experiment 2 |

the level of ttx produced by newts in areas where snakes exhibit a resistance between 1 and 10 mg ttx

the increase in the percent of ttx-producing newts at the alaska site over time

c. | experiment 1 | experiment 2 |

the decreasing range of toxicity and possible error measured as ttx resistance increases

the level of ttx produced by and the mean resistance of garter snakes at the alaskan site in year 1

d. | experiment 1 | experiment 2 |

the negative association between ttx production and ttx resistance across the 28 west coast sites

the increase in the average ttx-resistance in snakes in the alaskan site over time

Explanation:

To support the hypothesis that increased TTX - producing newts lead to more TTX - resistant snakes and adaptations beyond the threat, we analyze each option:

• Option A: For Experiment 1, just looking at TTX production in areas with snake resistance >10 mg TTX doesn't show the "beyond threat" part. For Experiment 2, only the increase in percentages of TTX - producing newts and resistant snakes doesn't show the adaptation beyond the threat (like increased mean resistance). So A is incorrect.

• Option B: Experiment 1's focus on TTX production in areas with snake resistance between 1 - 10 mg TTX doesn't support the "beyond threat" idea. Experiment 2 only considering the increase in TTX - producing newts' percentage also fails to show the adaptation beyond the threat. So B is incorrect.

• Option C: Experiment 1's "decreasing range of toxicity and possible error as TTX resistance increases" doesn't clearly support the hypothesis. Experiment 2 looking at year 1 data (a single time - point) can't show the trend over time related to the hypothesis. So C is incorrect.

• Option D: Experiment 1 shows a negative association between TTX production and TTX resistance across 28 west - coast sites, which implies that as newts (with TTX production) are around, snakes develop resistance. Experiment 2 shows an increase in average TTX - resistance in snakes over time at the Alaskan site, along with an increase in TTX - producing newts. This increase in resistance over time, even as newt TTX production is increasing, suggests that snakes are adapting beyond the initial threat level (since resistance is increasing more than just matching the newt's TTX production). So D provides the best evidence.

Answer:

D.
Experiment 1: the negative association between TTX production and TTX resistance across the 28 west coast sites
Experiment 2: the increase in the average TTX - resistance in snakes in the Alaskan site over time