Traits that are controlled by genes found on an X chromosome are said to be? Please provide an explanation?

Question

a) codominant

b)autosomal dominant

c)sex_linked

d)autosomal recessive

Answer 1

c) s*x-linked

If a gene is found only on the X chromosome and not the Y chromosome, it is said to be a s*x-linked trait. Because the gene controlling the trait is located on the s*x chromosome, s*x linkage is linked to the gender of the individual. Usually such genes are found on the X chromosome. The Y chromosome is thus missing such genes (See Diagram above.). The result is that females will have two copies of the s*x-linked gene while males will only have one copy of this gene. If the gene is recessive, then males only need one such recessive gene to have a s*x-linked trait rather than the customary two recessive genes for traits that are not s*x-linked. This is why males exhibit some traits more frequently than females.

From: http://ghs.gresham.k12.or.us/science/ps/...