A medical researcher experimented with the effects of calcium intake on the healing time of broken bones. People who had
similar broken bone injuries were divided randomly into two groups, one of which received a calcium supplement and one of
which received a placebo. The data showed that there was no significant difference in healing times between the two groups, so
the researcher concluded that calcium intake has no effect on bone healing time. Why is the conclusion of the researcher not
justified?
The researcher did not use a control group.
The bone injuries in different people cannot be compared.
The overall calcium intake of the two groups was not considered.
The data can only give a statistical probability, so no conclusion can be made.

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You will create a molecular clock model for an arthropod gene. follow these guidelines to make your model: . your timeline will span from 90 million years ago to the present. the common ancestor in your model is an arthropod that lived 90 million years ago. the gene that you'll track codes for a protein in the species venom . the dna sequence youll track contains 10 nitrogen bases. you can choose the order of the bases and where the mutations occur. this gene mutates at a rate of approximately 0.76 base pairs every 17.1 million years. to build your model,/ calculate the estimated time period it takes for 1 base pair to mutate. the first time period will only show the common ancestor. at the beginning of the second time period, three lineages will diverge from the common ancestor, each with a different mutation in their gene sequences. the first and third descendant species will survive for the rest of the timeline. the second descendant species was extinct 50 million years ago. calculate how long it will take for one full base pair mutation to occur. explain your reasoning by constructing a mathematical equation