Answer:
B.Genetic disorder cannot be caused by changes in just one individual gene.
Step-by-step explanation:
If we changes in a genes of DNA sequence can change proteins.
Because DNA is made up of proteins .Proteins are made up of amino acids .
Therefore, when we changes in genes of DNA is changes the sequence of amino acids will altered.
When the we change in genes f DNA then the phenotype may be change or may not be change . Because phenotypes means we can see directly in traits Therefore, sometimes when we change the genes ( both allele of a gene)of DNA its phenotype would be affected .When we changes genes of DNA then the chances of genetic disorders can be occurred .When we changes in genes in of sex chromosomes then the genetic disorder can be caused.For example when Y is replaced by XY then the sex chromosome of male is XXY .The genetic disorder is' kilnefelter syndrome'.
Therefore, option A, C and D are correct but option B is false.Because when we changes in genes of DNA then the genetic disorder can be caused by changes in just one individual gene.