Answer:
Covalent bonds appear inside every linear chain and connect bases, sugars, and phosphate groups.
Hydrogen bonds appear between two strands and involve the base from one strand with the base from another strand in the complementary pairing.
Step-by-step explanation:
A covalent bond is a chemical bond formed by joining electrons of two non-metal atoms into one or more common pairs.
A hydrogen bond (X-bond) is a type of weak chemical bond based on electrostatic attraction between a hydrogen atom and a nucleophilic atom that contains free electron pairs.