Answer:
D. The ability to allow materials to cross a membrane
Explanation:
It all has to do with the size of the materials trying to pass through. All other options do not make sense. Thickness, flexibility, and amount of molecules do not describe permeability.
CDNA does not have introns and therefore can be expressed in prokaryotic cells. cDNA libraries are most useful in reverse genetics where the additional genomic information is less use. Also, it is useful for subsequently isolating the gene that codes for that mRNA.
I believe the answer is Sex-linked traits
Sex-linked traits refer to the genetic traits that strongly tied to either X or Y chromosome, which make certain traits to become more likely to be possessed by a certain sex.
Another example would be the genes that make us able to grow facial hair are sex-linked to Y chromosomes. Facial hair would predominantly exist in males but on rare occurrence, it could exist in female