Question

the scientists accidentally smeared the labels so that the samples are no longer identifiable. the scientists use electrophoresis gels to compare the dna collected. the results of the two tests are shown.

which claim is best supported by the results of the gel electrophoresis?

a cells from the same species contain the same dna.
b cells from different tissues in the same organism contain different dna.
c all cells within a specific type of tissue have the same dna across organisms.
d all cells within the same organism, that are not sex cells, contain the same dna.

Explanation:

• Option A: Different individuals of the same species have different DNA (except identical twins). So this is incorrect.
• Option B: In the same organism (except sex - cells), all cells have the same DNA. Different tissues in the same organism have the same DNA but express different genes. So this is incorrect.
• Option C: Cells within a specific type of tissue from different organisms have different DNA. So this is incorrect.
• Option D: All non - sex cells within the same organism contain the same DNA. Gel electrophoresis results (if samples 1 and 2 are from the same organism, they have same banding pattern in the first test; samples 3 and 4 may be from different sources). This claim is in line with biological facts.

Answer:

D