In a dicot stem, the arrangement of vascular bundles is:
Answer: B
Dicot stems have vascular bundles arranged in a ring or eustele pattern, whereas monocots have scattered bundles.
Q.42Easy
Companion cells are exclusively associated with which of the following?
Answer: B
Companion cells are specialized parenchymatous cells that remain alive and are attached to sieve tube elements in the phloem.
Q.43Medium
The endodermis in a root is primarily involved in:
Answer: B
The endodermis contains the Casparian strip, which regulates the movement of water and solutes into the vascular cylinder.
Q.44Medium
Which anatomical feature is characteristic of C4 plants?
Answer: A
C4 plants exhibit Kranz anatomy where mesophyll cells and bundle sheath cells are specialized for different aspects of photosynthesis.
Q.45Easy
In a typical angiosperm leaf, the tissue responsible for gas exchange is primarily:
Answer: B
The spongy mesophyll contains intercellular spaces and is located below the palisade layer, facilitating gas exchange through stomata.
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Q.46Medium
Tracheids differ from vessels in that tracheids:
Answer: B
Tracheids are elongated, unicellular structures with tapering end walls and pits, unlike vessels which are multicellular with perforated end plates.
Q.47Medium
The Casparian strip is impregnated with which substance?
Answer: B
The Casparian strip in endodermis is impregnated with suberin, making it impermeable to water and solutes, thus forcing them through the endodermal cells.
Q.48Medium
Which of the following represents the correct sequence of tissue layers from outside to inside in a dicot stem?
Answer: C
In a young dicot stem, the sequence from outside is: cuticle, epidermis, cortex (containing hypodermis and endodermis), vascular bundles, and central pith.
Q.49Medium
In monocot roots, the pericycle is typically:
Answer: A
In monocot roots, the pericycle is usually uniseriate and gives rise to lateral roots, unlike in dicots where it's multiseriate.
Q.50Hard
The phenomenon where xylem and phloem are arranged on the same radii is called:
Answer: C
Radial arrangement is characteristic of monocot roots where xylem and phloem alternate on different radii. When they're on the same radii, it's called conjoint arrangement.
Q.51Medium
Which adaptation in desert plants helps reduce water loss through leaves?
Answer: B
Desert plants (xerophytes) have smaller leaves, thicker cuticles, and often sunken stomata to minimize water loss through transpiration.
Q.52Medium
In aquatic plants, the aerenchyma tissue functions primarily to:
Answer: B
Aerenchyma is specialized parenchyma with large air spaces that provides buoyancy and allows diffusion of gases in hydrophytes.
Q.53Medium
The cork cambium (phellogen) originates from:
Answer: C
The cork cambium originates from the endodermis or outer cortical cells and produces cork and phelloderm as part of the periderm.
Q.54Easy
Which of the following is NOT a function of collenchyma?
Answer: C
Collenchyma provides mechanical support with flexibility but does not transport water and minerals; that function belongs to xylem.
Q.55Medium
The xylem in angiosperms is primarily composed of:
Answer: C
Angiosperm xylem consists of vessels (main conducting element), tracheids, xylem parenchyma (storage), and xylem fibers (support).
Q.56Hard
In a typical leaf petiole, the arrangement of vascular bundles is:
Answer: C
Petioles contain multiple vascular bundles arranged in characteristic patterns - often arc-shaped or scattered, providing strength and flexibility.
Q.57Hard
The stele in roots includes all of the following EXCEPT:
Answer: D
The stele consists of pericycle, vascular tissues, and endodermis. The cortex lies outside the endodermis and is not part of the stele.
Q.58Medium
Which anatomical adaptation is specific to insectivorous plants like pitcher plants?
Answer: B
Insectivorous plants have anatomically modified leaves (pitchers, traps) with specialized glandular and digestive tissues to trap and digest insects.
Q.59Hard
The histogen theory explains the origin of root tissues from three meristematic zones. Which zone gives rise to the root cap?
Answer: D
According to the histogen theory, the calyptrogen (root cap mother region) produces the root cap, while dermatogen produces epidermis, periblem produces cortex, and plerome produces stele.
Q.60Easy
Which of the following tissues is responsible for secondary growth in dicot stems?
Answer: A
Vascular cambium produces secondary xylem and phloem, while cork cambium produces cork and secondary cortex, together contributing to secondary growth.
