1. The problem asks to identify the part of the DNA segment labeled X. 2. DNA consists of a double helix structure with two strands connected by specific components: - Phosphate group: part of the backbone of DNA. - Deoxyribose: sugar molecule in the backbone. - Nucleotide: the basic unit of DNA, consisting of a phosphate, sugar, and base. - Hydrogen bond: the weak bond connecting complementary bases between the two strands. 3. The label X points to the short line connecting the two strands, which represents the hydrogen bonds holding the complementary bases together. 4. Therefore, the correct identification for the part labeled X is the Hydrogen bond. Final answer: Hydrogen bond