Free Biodiversity and Variety of Life MCQs with Answers

1851. What happens in plants during vascularisation?

• A. Differentiation of procambium, formation of primary phloem followed by formation of primary xylem
• B. Differentiation of procambium followed by the formation of primary phloem and xylem simultaneously
• C. Formation of procambium, primary phloem and xylem simultaneously
• D. Differentiation of procambium followed by the formation of secondary xylem

Explanation: In plants during vascularisation, differentiation of procambium occurs followed by the formation of primary phloem and xylem simultaneously. The primary xylem is responsible for transporting water and minerals from the roots to the leaves. Primary phloem is responsible for transporting sugars and other organic compounds from the leaves to the rest of the plant. Secondary xylem and secondary phloem are formed from vascular cambium, which is a meristematic tissue that develops from procambium. The secondary xylem and secondary phloem form in concentric rings around the stem or root, increasing the thickness of the vascular system.

1852. What is true about a monocot leaf?

• A. Reticulate venation
• B. Absence of bulliformcells from epidermis
• C. Mesophyll not differentiated into palisade and spongy tissues
• D. Well-differentiated mesophyll

Explanation: In monocot leaf, mesophyll cells are not differentiated into palisade and spongy tissues. But there are well differentiated mesophyll cells in the dicot stem. Also in the upper epidermis, there are some large cells found in groups which are called bulliform cells. The venation pattern in the monocot is parallel.

1853. Which is correct about the transport of conduction of substances?

• A. Organic food moves up through phloem
• B. Organic food moves up through xylem
• C. Inorganic food moves upwardly and downwardly through xylem
• D. Organic food moves upwardly and downwardly through phloem

Explanation: Phloem is the food-conducting tissue of plants. The sieve tubes are food-conducting elements of the plants. It is proposed that food is translocated by mass flow or by streaming currents of protoplasm. The movement of organic food materials or the solutes in soluble from one place to another in higher plants is called as translocation of organic solutes. Protoplasmic streaming occurs in sieve tube elements of phloem and the solute molecules caught up in the circulating cytoplasm are carried from one end to the other end of the sieve tube from where they diffuse to the next sieve tube elements through the cytoplasmic strands in the sieve plates.

1854. An organized and differentiated cellular structure having cytoplasm but no nucleus is:

• A. Vessels
• B. Xylem parenchyma
• C. Sieve tubes
• D. Tracheids

Explanation: An organised and differentiated cellular structure having cytoplasm but no nucleus are sieve tubes. The sieve tubes are living cells. Their walls are thicker than surrounding parenchyma cells. Sometimes they havea special, shining nacreous thickening. Cytoplasm occurs in the form of thin lining enclosing a big central vacuole.

1855. The space between the overtopped dichotomous branches was occupied by a sheet at which cells during evolution of megaphylls?

• A. Sclerenchyma
• B. Parenchyma
• C. Collenchyma
• D. Chlorenchyma

Explanation: During the evolution of megaphylls, the spaces between the overtopped dichotomous branches were occupied by a sheet of parenchyma cells. This process, known as webbing or web formation, resulted in the development of expanded lamina or leaf blade with a network of veins.

1856. Cycas has two cotyledons but is not included in angiosperms because of:

• A. Naked ovules
• B. Seems like monocot
• C. Circinate ptyxis
• D. Compound leaves

Explanation: Cycas is a gymnosperm with exposed ovules (not enclosed in an ovary), unlike angiosperms.

1857. Protista evolved from prokaryotes but which one of the following evolved from protista:

• A. Fungi
• B. Plantae
• C. Animalia
• D. All of these

Explanation: All three groups-Fungi, Plantae, and Animalia-evolved from protists, sharing a common eukaryotic ancestors.

1858. Which one of the following statements about Cycas is incorrect?

• A. It has circinate vernation
• B. Its xylem is mainly composed of xylem vessel
• C. Its roots contain some blue-­green algae
• D. It does not have a well-organized female flower

Explanation: Cycas lacks xylem vessels; it has only tracheids, unlike angiosperms.

1859. Largest sperms in the plants world are found in:

• A. Banyan
• B. Cycas
• C. Thuja
• D. Pinus

Explanation: Cycas produces large, visible, motile sperms which is the largest among plants.

1860. Ulothrix can be described as a:

• A. Filamentous alga lacking flagellated reproductive stages
• B. Membranous alga producing zoospores
• C. Filamentous alga with flagellate reproductive stages
• D. Non-­motile colonial alga lacking zoospores

Explanation: Ulothrix produces flagellated reproductive cells and is filamentous in shape.