Ans. (B). Genes.
The chemicals that kill the weeds are known as herbicides. Herbicide-resistance is defined as the inherited ability of weeds to survive an application of herbicide, that can kill a normal weed plant of same species.
The resistance develops due to mutations in genes that were sensitive to those chemicals in wild-type forms. As genes are responsible for transfer of characteristics from one to another generation, the herbicide-resistance is also passed down to generations through genes.
Thus, the correct answer is option (B).
The best way is to compare the DNA of the two species. The more nitrogenous bases and amino acids two species have in common, the more closely related they are.
Carbon, hydrogen and oxygen.
How about "recombinant DNA?" Which is the result of DNA cloning as ttom suggests.
