C
Because your DNA is made of nitrogen bases
Adenine
Guanine
Cytosine
Thymine
Perhaps the bird’s calls could be less attracting and disorienting to predators and the ones with the said distinctive calls could have survived to repopulate and pass down the genes.
Immigration and emigration is typically done with the purpose of looking forward to a better and more prosperous life, a more comfortable life where the money you earn can last you a pretty long time and buy you enough thing to live more comfortable than where you used to live. Therefore, when you move to a prosperous country, having children is not something you’ll worry about given to the commodities you’ll have and the easy access to baby food and baby clothes and stuff, therefore, when people emigrate/immigrate to more prosperous countries, they’re comfortable with the idea of having more children, and that leading to population growth.
Answer:
it creates new combinations of genetic material in the 4 daughter cells