Concept:The endomembrane system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles.
Mitochondria and plastids are double‑membrane‑bound organelles with their own circular DNA.
Key Fact:The ribosomes on rough endoplasmic reticulum synthesize proteins.
The cytoskeleton is composed of microtubules, microfilaments, and intermediate filaments.
Mitochondria are not part of the endomembrane system.
Explanation:Statement A is false because mitochondria are not included in the endomembrane system.
Statement B is true: rough endoplasmic reticulum bears ribosomes on its cytoplasmic surface.
Statement C is true: both mitochondria and plastids contain circular DNA, a characteristic of semi‑autonomous organelles.
Statement D is true: the network of microtubules, microfilaments, and intermediate filaments in the cytoplasm is called the cytoskeleton.
Statement E is false: the mitochondrion is a double‑membrane‑bound structure, not single‑membrane‑bound.
Thus, the correct statements are B, C, and D.
Answer:Option D: B, C and D only.
