How do birds' songs change in response to changes in their environment?

https://phys.org/news/2009-05-bird-songs-environment.html

Explanation:

answer///multiple alleles;

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: