Free Biodiversity and Variety of Life MCQs with Answers

1961. A bicollateral vascular bundle is characterized by:

• A. Phloem being sandwitched between xylem
• B. Transverse splitting of vascular bundle
• C. Longitudinal splitting of vascular bundle
• D. Xylem being sandwitched between phloem

Explanation: A bicollateral vascular bundle is characterized by the xylem being sandwiched between the phloem. Here there are two cambuim rings e.g., Cucurbita. In a bicollateral vascular bundle, the xylem is sandwiched between two layers of phloem. This arrangement is different from a collateral vascular bundle, which has a phloem located on only one side of the xylem.

1962. Angular collenchyma occurs in:

• A. Cucurbita
• B. Helianthus
• C. Althaea
• D. Salvia

Explanation: Angular collenchyma is a type of collenchyma, a supportive tissue found in plants, that is characterized by thickenings in the cell walls at the corners of the cells. This type of collenchyma is found in the stems and leaves of Cucurbita plants, which include pumpkins, melons, and squashes.

1963. Half-inferior ovary and perigynous flowers are present in

• A. Cucumber
• B. Guava
• C. Brinjal
• D. Plum

Explanation: The ovary in the flowers of a plum is half-inferior. The receptacle is embedded or surrounded by a half-inferior ovary. Flowers such as these are called perigynous or half-epigynous. Half-inferior ovaries are not known in some classifications and are classified with either the dominant or inferior ovaries instead. If sepals, petals and stamens are inserted under the ovary, the flower is considered to be hypogynous. The thalamus forms a cup-shaped structure around the ovary in perigynous flowers, and sepals, petals, and stamens tend to be inserted on the cup surface. The flower is said to be epigynous as the thalamus fully encloses the ovary and fuses with the ovary wall and sepals, petals and stamens appear to emerge above the ovary.The anther is the end of the stamen where the pollen is found. Three sections are made of the pistil: the ovary, the style and the stigma. In order to produce a seed, the ovary produces ovules that need to be fertilised. An egg nucleus and polar nuclei are found in the ovules.

1964. Classification given by Bentham and Hooker is

• A. artificial
• B. natural
• C. phylogenetic Answer Key
• D. numerical

Explanation: Classification given by Bentham and Hooker is Natural System. Monocots were placed after dicots; closely related families were seperated; gymnosperms were placed between dicots and monocots.

1965. In ginger, vegetative propagation occurs through:

• A. Bulbils
• B. Runners
• C. Rhizome
• D. Offsets

Explanation: The rhizome is a thickened, underground, dorsoventral stem that grows horizontally at a particular depth within the soil. It is brown in color and shows cymose branching. It can be distinguished from the modified root by the presence of nodes, internodes, terminal buds, axillary buds, and scale leaves. The rhizomes are perennial and propagate vegetatively. They store food materials and appear tuberous. E.g., Zingiber officinale (ginger), Curcuma longa (turmeric), Canna indica.A bulbil is a small, young plant that is reproduced vegetatively from axillary buds on the parent plant's stem or in place of a flower on an inflorescence. These young plants are clones of the parent plant that produced them-they have identical genetic material.A runner is a slender stem that grows horizontally along the ground, giving rise to roots and aerial (vertical) branches at specialized points called nodes.An offset (also called a pup) is a small, virtually complete daughter plant that has been naturally and asexually produced on the mother plant.

1966. Flowers which have a single ovule in the ovary and are packed into inflorescence are usually pollinated by:

• A. Bee
• B. Wind
• C. Bat
• D. Water

Explanation: A single ovule in the ovary and flowers packed into inflorescence are characteristics of wind-pollinated flowers.Pollen are light weight and non-sticky which leads to easy dispersal of the pollen from anther to stigma of the flower by wind.

1967. Pollination in water hyacinth and water lily is brought about by the agency of:

• A. Water
• B. Insects or wind
• C. Birds
• D. Bats

Explanation: In aquatic plants with emergent flowers e.g., water lily and water hyacinth, pollination takes place by wind or insects.Emergent plants are rooted with stiff or firm stems and stand above the water surface.

1968. The ovule of an angiosperm is equivalent to:

• A. Megasporangium
• B. Megasporophyll
• C. Megaspore mother cell
• D. Megaspore

Explanation: The ovule of an angiosperm is equivalent to a megasporangium which consists of 2 synergids, 1 egg, 3 antipodal cells, and a secondary nucleus. B. Megasporophyll is a type of leaf-like structure produced by heterosporous plants such as seed plants, lycophytes, and some ferns.C. Megaspore mother cell (2n) gives rise to the ovule.D. Spores produced by megasporangium are called megaspores.

1969. Double fertilization is exhibited by:

• A. Algae
• B. Fungi
• C. Angiosperms
• D. Gymnosperms

Explanation: Double fertilization is the characteristic feature of angiosperms. Here, two male gametes are released in the embryo sac or female gametophyte. One male gamete fuses with the egg cell to form a zygote that gives rise to the embryo whereas the other male gamete fuses with the two polar nuclei to form a triploid 3n nucleus in the center of large central cell of the embryo sac. This large cell will give rise to endosperm, a food storing tissue.STB page #99FTB page # 182- 184

1970. Filiform apparatus is a characteristic feature of:

• A. Aleurone cell
• B. Synergids
• C. Generative cell
• D. Nucellar embryo

Explanation: The filiform apparatus is a mass of finger-like projections of the wall into the cytoplasm. It is present in synergids (help cells) of the embryo sac, in the micropylar region. It guards the pollen tube inside the ovule towards the embryo sac. A special cellular thickening present in the synergids at the micropylar end is called filiform apparatus. After fertilization when the egg cell gives rise to a zygote, they get disorganized. The major function is to guide the entry of pollen tubes into synergids and to release sperm cells.