Which of the following statements are true for stamen and microsporngium?

(i) A typical angiosperm anther is bilobed, dithecous.

(ii) The microsporangia develop further and become pollen sacs.

(iii) Microsporangium generally surrounded by four wall layers.

(iv) The epidermis, endothecium and middle layers of anther perform the function of protection.

(v) The innermost wall layer of anther is the tapetum and it nourishes the developing pollen grains.

(vi) Cells of the tapetum generally have one nucleus.