- Which of the following cells are found in phloem but not in xylem?
a) Fibers
b) Tracheids
c) Sieve tubes
d) Parenchyma
Answer: c) Sieve tubes
Explanation: Sieve tubes are a characteristic component of phloem and are involved in the transport of sugars and other organic substances. Xylem contains tracheids but not sieve tubes.
- Which type of meristem is responsible for the elongation of roots and shoots?
a) Apical meristem
b) Lateral meristem
c) Intercalary meristem
d) Vascular cambium
Answer: a) Apical meristem
Explanation: Apical meristems are found at the tips of roots and shoots and are responsible for the primary growth, or elongation, of the plant body.
- Which of the following is NOT a component of xylem?
a) Tracheids
b) Vessels
c) Companion cells
d) Xylem parenchyma
Answer: c) Companion cells
Explanation: Companion cells are part of the phloem and help in the functioning of sieve tubes. Xylem contains tracheids, vessels, fibers, and parenchyma.
- The Casparian strip in the endodermis is composed of:
a) Lignin
b) Suberin
c) Pectin
d) Cellulose
Answer: b) Suberin
Explanation: The Casparian strip, present in the endodermal cells, is composed of suberin, a waxy substance that makes these cells impermeable to water, regulating the movement of water and minerals into the vascular tissue.
- Which of the following tissues forms the bulk of the wood in a tree?
a) Primary xylem
b) Secondary xylem
c) Phloem
d) Cork
Answer: b) Secondary xylem
Explanation: The secondary xylem, produced by the vascular cambium, constitutes the bulk of the wood in trees. It is responsible for water transport and provides structural support.
- Which tissue is responsible for the formation of annual rings in trees?
a) Epidermis
b) Cortex
c) Vascular cambium
d) Phloem
Answer: c) Vascular cambium
Explanation: The vascular cambium produces secondary xylem and secondary phloem each year, and the differential growth during different seasons forms annual rings in the wood of trees.
- In monocot roots, vascular bundles are typically:
a) Conjoint
b) Radial
c) Collateral
d) Bicollateral
Answer: b) Radial
Explanation: In monocot roots, the vascular bundles are arranged in a radial manner, meaning that the xylem and phloem are located on separate radii.
- Which of the following is a characteristic feature of a monocot leaf?
a) Reticulate venation
b) Parallel venation
c) Open vascular bundles
d) Presence of cork cambium
Answer: b) Parallel venation
Explanation: Monocot leaves typically have parallel venation, in which the veins run parallel to each other from the base to the tip of the leaf.
- Which of the following tissues lacks lignin?
a) Collenchyma
b) Sclerenchyma
c) Xylem
d) Cork
Answer: a) Collenchyma
Explanation: Collenchyma cells have thickened cell walls due to cellulose and pectin, but they do not contain lignin. Sclerenchyma, xylem, and cork have lignified walls.
- Which type of root system is most commonly found in dicots?
a) Fibrous root system
b) Adventitious root system
c) Taproot system
d) Prop root system
Answer: c) Taproot system
Explanation: Dicots typically have a taproot system, where a single main root grows deep into the soil with lateral roots branching off it.
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