Which molecule would require the use of energy in order to be brought into the ?

What is the ecological role of food chains and food webs

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.

What is any method of measuring the age of an object or event in years, such as using atomic half-life?