C.               Chemical components of genes ANSWERS

(1)    In most organisms, the coded instructions for specifying the
   characteristics of the organism are carried in

         D N A   molecules formed from subunits known as nucleotides.
    These nucleotides which have major portions in common also have
    subparts which differ.

 

         These four different subparts of a  N U C L E O T I D E  are kinds of  
    B A S E S.  (Link!)
    One is Guanine represented by the letter  G
    One is Cytosine represented by the letter  C
    One is Adenine represented by the letter   A
    One is Thymine represented by the letter  T.
  
 
These four letters are the parts of the DNA molecule which differ and
allow genes to differ between individuals and between species.

(2)    The chemical and structural properties of DNA are the basis for how
the genetic information that makes up (underlies) heredity is both
encoded in
        G E N E S  (as a string of molecular “B A S E S”) and

 

    R E P L I C A T E D  (this means copied exactly)
    by means of a    T E M P L A T E  (example)
    (pattern of bases).