Create a dichotomous key that identifies the 10 leaves on the Common Leaves sheet. Look closely at those leaf
samples and devise a dichotomous key that helps you identify them. Be sure that your dichotomous key contains
only pairs of statements about a single characteristic. For example, a pair of statements might be:
A leaf margin smooth
B. leaf margin toothed

a.) a destruction fo cells by viral reproduction

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

substitution is the answer in this case