4. Which of the following is correct:
(a) Cells of all living organisms have a nucleus.
(b) Both animal and plant cells have a well defined cell wall.
(c) In prokaryotes, there are no membrane bound organelles.
(d) Cells are formed de novo from abiotic materials.
The correct statement is (c) In prokaryotes, there are no membrane bound organelles. All other statements are incorrect as cells of some organism can lack a nucleus (e.g. RBC ), animal cells do not possess a cell wall and cells are formed from pre-existing cells.