Question

Comparable segments of the mitochondrial DNA sequences of two similar species are shown below. This segment of DNA mutates at a rate of one base pair per 33 million years. Based on these DNA sequences, how long ago did the two species diverge from a common ancestor?

Species A mtDNA sequence: TACAAGATAC
Species B mtDNA sequence: TACGCGTAAC

99 million years ago

33 million years ago

66 million years ago

132 million years ago

I said 66 million years ago because there are four differences so u multiply 4 and 33 but i thought u hd to divide by 2 for each species.

Answer 1

you don't need to divide by 2 for each species because you are comparing species A to species B

Answer 2

oh ok thanks a lot

Answer 3

can u help me with another question? @agreene

Answer 4

sure

Answer 5

A pharmaceutical company is testing a new drug. For the study, the company enrolled 200 people who had previously been diagnosed with a specific condition. Half took the study drug and half took a placebo. Throughout the study, the participants were routinely asked to fill out a 50-question survey. After six months, the participants on the study drug showed positive improvements in their answers. What is the best way the company could improve this study to prove more thoroughly that its medications work?

Decrease the proportion of placebo subjects to be less than half of the test population.

Combine results of the survey with quantitative data, like blood tests or brain scans.

Increase the length of the survey to 100 questions to check for statistical anomalies.

Include test subjects who have been diagnosed with a similar condition.

I put the second one

Answer 6

you would be correct

Answer 7

oh ok thanks a ton