The antiparallel arrangement within dna molecules refers to select one:
a. each base bonding at the 1' position of the sugar.
b. a purine always bonding to a pyrimidine.
c. one helix strand that runs from the 5' to 3' direction and the other strand runs from the 3' to 5' direction.
d. an original parent dna strand and one newly synthesized dna strand comprising a new dna molecule.

c. one helix strand that runs from the 5' to 3' direction and the other strand runs from the 3' to 5' direction.

Explanation:

A DNA molecule has two strands of nucleotides with a sugar phosphate backbone each, but orientated on the opposite direction allowing for the base pairs to complement one another, making it a more stable structure. When two biopolymers run parallel to each other but with opposite directionality (alignment) we have an antiparallel arrangement.

I annexed an image of the DNA structure.

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i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

the farther away the object is from the central star (the sun) it's gravitainal pull on the object is weaker when it is farther

explanation: