Explain what is meant by the antiparallel polarity of the two strands of dna within the double helix.

The two DNA strands have anti parallel polarity which means that they are directional and anti parallel to each other. The polarity to these strands is conferred by the deoxyribose sugar molecule in nucleotide. The sugar molecule has 5 Carbon atoms. The third carbon is attached to an OH group and the fifth carbon is attached to a phosphate molecule. This asymmetry is responsible for giving DNA molecule a direction.

The double helix structure has both these strands in opposite direction so that the 5 prime carbon of one strand faces the 3 prime carbon of another. The anti parallel structure of DNA strands lets the base pairs complement each other. Anti parallel structure is also more stable than parallel structure.  

b is the correct answer

plato users:

d.  

there was a variety of food available on island x, but there were only large seeds and nuts on island y.