STD 12 - 1. sexual reproduction in flowering plants — NEET STD 11 Science — Question

Which one of the following statements are correct ?
(i) Dicot root always have 2-4 xylem and phloem patches.
(ii) All tissues on the inner side of the endodermis such as pericycle, vascular bundles and pith constitute the stele.
(iii) There are usually less than six xylem bundles in the monocot root.
(iv) The outer hypodermis consists of few layers of collenchymatous cells just below the epidermis, which provide mechanical strength to the young stem.
(v) The cells of the hypodermis are rich in starch grains and the layer is also referred to as the starch sheath.
(vi) A large number of vascular bundles are arranged in a ring; the 'ring' arrangement of vascular bundles is a characteristic of dicot stem.
(vii) The monocot stem has a sclerenchymatous hypodermis and a large number of scattered vascular bundles.
(viii) The adaxial epidermis generally bears more stomata than the abaxial epidermis.
(ix) The sizes of the vascular bundles are dependent on the size of the veins.
(x) In grasses, certain adaxial epidermal cells along the veins modify themselves into large, empty, coloured cells. These are called buliform cells.
(xi) The tissues involved in secondary growth are the two lateral meristems: vascular cambium and cork cambium.
(xii) In dicot stems, the cells of cambium present between primary xylem and primary phloem is the intrafascicular cambium.
(xiii) The cells of medullary rays adjoining interfascicular cambium become meristematic and form the intrafascicular cambium.
Choose the correct option given below :-

When food supply is poor, the rate of growth is

What is correct for chlorophycae ?

Which of the following are true statement for monocotyledonous leaf ?
(i) Stomata are present on both the surfaces of the epidermis.
(ii) Mesophyll is not differentiated into palisade and spongy parenchyma.
(iii) In grasses, certain abaxial epidermal cells along the veins modify themselves into bulliform cells.
(iv) When the bulliform cells in the leaves have loss water, the leaf surface is exposed but when they absorbed water make the leaves curl inwards to minimise water loss.
(v) The size of the vascular bundles are dependent on the size of the veins.

If a leaf segment of Bryophyllum plant is in soil, it produces new plants. This is because its leaf has

How many statements are wrong for Botanical gardens ?
(i) Museum may be set up in educational institutes.
(ii) Museums have collections of preserved plant and animal specimens
(iii) Specimens are not preserved in the jars in preservative solutions.
(iv) Plant and animal specimens may also be preserved as dry specimens
(v) Insects are preserved in insect boxes after collecting, killing and pinning
(vi) Small animals are usually stuffed and preserved.
(vii) Museums often have collections of skeletons of animals