In a population of birds intermediate beak size is selected against and both very small and very large beak sizes are favored. What type of selection is this an example of?

The double bond between a carbon atom and two oxygen atoms (a molecule of carbon dioxide) has two characteristics. what are they? a.an ionic bond is formed between the oxygen and carbon atoms. b.four valence electrons are shared. c.two valence electrons are shared. d.valence electrons are shared between oxygen atoms.