The planetary body that Spirit was designed to explore the wide ranges of soil and rocks for clues of the water activity on Mars. Spirit specifically landed at the Gusev Crater which was before, a possible lake in a giant crater. 
        
             
        
        
        
A molecule.
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Answer:
covalent bonds
Explanation:
Nucleotides are joined together by covalent bonds between the phosphate group of one nucleotide and the third carbon atom of the pentose sugar in the next nucleotide.