Which structure is part of the nucleus along with the nucleolus and chromatin?

• A. Nuclear envelope
• B. Endoplasmic reticulum
• C. Mitochondria
• D. Lysosome

Answer: (A)

The nucleus contains genetic material organized as chromatin and includes the nucleolus, but its defining boundary is the nuclear envelope. This envelope is a double membrane that surrounds the nucleus and has nuclear pores to control movement between the nucleus and the cytoplasm. Because the question asks for a structure that is part of the nucleus alongside the nucleolus and chromatin, the nuclear envelope is the correct choice. The other organelles—endoplasmic reticulum, mitochondria, and lysosomes—reside in the cytoplasm and are not components of the nucleus.