13. Which of the following are examples of complementary bases? A. cytosine and guanine
B. guanine and thymine
C. thymine and cytosine
D. cytosine and adenine

14. Guanine and cytosine are held together by what type of bonds?
A. ionic bonds
B. peptide bonds
C. covalent bonds
D. hydrogen bonds
DNA molecule is T-A-G-T-C-A. what is

Which of these statements best describes the st. lawrence seaway? the st. lawrence seaway connects the st. lawrence river with the arctic ocean. the st. lawrence seaway provides an important trading route between the u.s. and mexico. the st. lawrence seaway provides an important trading route for the u.s, but has little value for canada. the st. lawrence seaway connects the great lakes, the st. lawrence river, and the atlantic ocean.

Which best compares habitat and niche? o niche is a place in which organisms live, and habitat is the way in which an organism fits into its habitat.o habitat is a place in which organisms live, and niche is the way in which an organism fits into its habitat.habitat is a group of organisms that live in an area, and niche is a specific species that lives in that areao niche is a group of organisms that live in an area, and habitat is a specific species that lives in that area.

Restriction enzymes are used in making recombinant dna. describe the role restriction enzymes perform when constructing recombinant dna.