Most likely the students are using a crude measurement of time, like a stopwatch. They would get the best results with a scientific apparatus that uses a computer and optical sensors. Even recording their dropped objects with a video camera and analyzing the video would give more consistent results. Results will also vary greatly if different people are taking the time measures instead of one person making all measurements.
The genotype would be X'Y for the father (he would be colorblind)
The genotype would be X'X for the mother (she would be a carrier)
The offspring would be X'X' _ X'X_ X'Y_ XY
The ratio would be 1:1 normal to colorblind
Hope this was helpful(;
<span> Biotic components or biotic factors are any living organisms that affect another
organism. These components shape an ecosystem which includes animals that
consume organisms in question and its living food that the said organisms
consume. Biotic components include human influence. Producers, consumers and
decomposers usually comprise biotic components.</span>
<span> </span>
The answer is that they treat bacterial infections.