What pattern of interaction would you expect between the tree, shrub, and grass?

How does the author's purpose in this passage differ from an author writing about her personal struggle living with asthma?

This is a biological reaction due to a stimulus. i need this quickly !

The structure of a dna molecule is best described as a. one long strand of nucleic acids b. two strands of dna nucleotides joined by hydrogen bonds c. two strands of amino acids joined by hydrogen bonds d. one long strand of amino acids