Explain why sex-linked traits are more often expressed in males. Your answer must
include an explanation of sex chromosomes and dominant and recessive alleles.

sex linked traits are more often expressed in males because of the X chromosome.  Males inherit the chromosome from their mother.  Most of these traits are found in the X chromosome.  The father only inherits the Y chromosome.  

Explanation:

If you are a male you will have an XY and if you are a female you will have an XX.  You will get one chromosome from each parent that will determine your sex. The mother will give you an X and the father can give you an X or Y.

cell division is not regulated in tumor cells.