In humans the gene for brown eyes is dominate over the gene for blue eyes which is recessive. If two blue eyed parents have six children how many of their children will have blue eyes?

three or four

Explanation:

if you think about it parent with both blu eyed doesn't exactly mean that because of that all their children will have blue eyes...

three out of six of them will have it the remaining four will probably have light or dark brown

then that particular organisms become extinct.

as resources become scarce because of population growth, the growth decreases after few years due to lack of resources and food.