Studies of Phenylketonuria (PKU) Provide Particularly Strong Evidence for the Conclusion

Multiple Choice

Studies of phenylketonuria (PKU) provide particularly strong evidence for the conclusion that

A) when some people fail to use some ability, that ability grows weaker and weaker in later generations.
B) X-linked recessive genes express their effects more strongly in males than they do in females.
C) all mammals are descended from a common ancestor.
D) changes in the environment can alter the outcome of a condition that is under genetic control.