( A ) the proportion of adenine in relation to thymine varies with the organism
( B ) there are two strands which run parallel in the $5'\rightarrow 3' $ direction
( C ) there are two strands which run antiparallel one in $5'\rightarrow3'$ direction and other in $3'\rightarrow 5'$
( D ) the total amount of purine nucleotides and pyrimidine nucleotides is not always equal
