Help plz asap! What are the organisms still alive that display some of the earliest vertebrate evolutionary characteristics?

How does photosynthesis show the conservation of mass and energy?

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.

To confirm when to exclude children from school it’s recommended that you refer to guidelines from which of the following organizations