STD 11 - 5. Morphology flowering plants — NEET STD 11 Science — Question

Which of the following causes delaying of senescence

The side effects of heavy and constant grazing is that the

The companion cells are specialized ........ which are closely associated with sieve tube elements.

Which of the following statements about tissue system is true ?
(i) Epidermal cells are parenchymatous with at small amount of cytoplasm lining the cell wall and a large vacuole.
(ii) The outside of the epidermis is often covered with a waxy thick layer called the cuticle which present in root and other part.
(iii) In grasses, the guard cells are bean shaped.
(iv) The outer walls of guard cells are thick and the inner walls are highly thin.
(v) Sometimes, a few epidermal cells, in the vicinity of the guard cells become specialised in their shape and size and are known as subsidiary cells.

Which one of the following statements are correct ?
(A) The arrangement of ovules within the ovary is known as placentation.
(B) In marginal placentation the placenta forms a ridge along the ventral surface of the ovary and the ovules are borne on this ridge forming one row as in pea.
(C) When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile, as in china rose, tomato and primrose.
(D) When the ovules are borne on central axis and septa are absent as in Dianthus and lem on the placentation is called free central.
(E) In sunflower and marigold, the placentation is basal.
(F) Fruit is a mature or ripened ovary, developed before fertilization
(G) If a fruit is formed without fertilization of the ovary, it is called a parthenocarpic fruit.
(H) In mango and coconut, the fruit is known as a drupe which develop from monocarpellary inferior ovaries and are one seeded.
(I) In coconut which is drupe, the mesocarp is fibrous.
(J) A seed is made up of a seed coat and an embryo.
(K) The seed coat has two layers, the inner testa and outer tegmen.
(L) The hilum is a scar on the seed coat through which the developing seeds were attached to the fruit.
(M) At the two ends of the embryonal axis are present radicle and plumule.
(N) In some seeds such as castor the endosperm formed as a result of double fertilization, is a food storing tissue.
(0) The outer covering of endosperm separates the embryo by a starch layer called aleurone layer.
Choose the correct option given below :-

Fimbriae are

The development of young embryos of pteridophytes within the female gametophytes is a precursor to the

Under favourable conditions Mucor reproduces