a/an is characteristic of children at age five.                a.  choice of same-sex playmates      b.  understanding of the ramifications of one's actions      c.  desire to play with children of different ages      d.  awkwardness with emerging motor skills

scientists have discovered that hiv does not cause aids by the virus's direct effect on the host's immune cells, but rather through the cells' lethal influence on one another. researchers from the gladstone institutes have revealed that hiv does not cause aids by the virus's

i believe it's c. the trait for large beaks will be passed on to future generations through natural selection.

since eventually smaller beaks would have to find another source of food or even eventually just die out from the lack of food.