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.

Explain the difference between incomplete dominance and codominance

Johnny rode his bike 4 blicks down the street to his friend's house once he got to his friend house and realized he could not cone out to play he turned aroubd and went back home. what is displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

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.