Answer:
They have a backbone, most use legs,wings,or fins for movement.
One option is that the samples run through gel electrophoresis is too small to be recognized (shorter strands of DNA travel further through the gel and larger strands travel shorter). The other option in that the restriction enzyme did not cut the DNA in the proper spot or there was a mutation in the bases that allowed for a mistake in the cutting; that is why there are 800 base pairs in one sample (that's a lot) An example of a mutation is that lets say the restriction enzyme was supposed to cut at the second G in GGACC. But if that G was turned into an A, then the restriction enzyme wouldn't cut there.
For number 5, you might have 800 because of the restriction enzyme cutting it wrong, a mutation that allowed for the cutting to not take place, or a fault in the sample taking.
I am an AP Biology student right now in Wisconsin. I just finished that worksheet this morning :) anymore questions just hit me up
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