g the inability to metabolize phenylalanine is a recessive autosomal trait called PKU when A marries a woman at random from another town what is the probability that his first born will be affected by PKU

The correct answer is - zero percent.

Explanation:

As it is known that PKU is a disease that takes place if one has wild type recessive rr only. It is given that A is normal heterozygous and if he marries normal women then

   R       r

R  RR    Rr

R   RR    Rr

so there will be 2 carriers and 2 unaffected but no affected.

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.