Which of the following statements are incorrect about thallophyta?

(i) Sex organs are unjacketed and one-celled gametangia.
(ii) The vascular system is well developed.
(iii) An embryo stage is absent.
(iv) The plant body is differentiated into root, stem, and leaves.

The correct option is D (ii) and (iv)
Thallophyta: salient features are- most primitive and simple plants. They do not possess a vascular system. The plant body is not differentiated into stem roots and leaves. The whole plant body remains in the form of an undivided mass of cells called thallus. The mode of nutrition is photosynthetic, parasitic or saprophytic. They reproduce both sexually and asexually. Asexual reproduction usually reproduction takes place by spore formation. Fertilization is not followed by embryo formation. The division Thallophyta includes two major classes, algae and lichens.