Answer:
nuclear envelope
Explanation:
Nucleus. It is a spherical double membrane-bound cell organelle that contains the genetic material of the cell. Nuclear membrane or Nuclear envelope: A double-membrane structure that separates cytoplasm from the nucleus.
Cell
Organelles
Nucleus
Answer: B
Explanation: Aphthous ulcers are white, round, or oval lesions surrounded by a red halo that appear on the buccal mucosa.