True or false when the mouth develops from the first opening in the gastrula the organism is called a deuterostome

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.

Which of the following can be assumed about the layers in areas 2 and 4

Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to the rest of the body?