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Right choice is (b) Heart wood

To explain: The region in the SECONDARY phloem that comprises of dead elements and PROTECTED by lignified WALLS is called Heart wood. Heart wood doesn’t conduct water but instead PROVIDES MECHANICAL support.

Correct choice is (d) Cork is also known as Phelloderm

The best I can explain: Cork cambium HELPS in the replacement of the broken epidermis during the secondary GROWTH. CELLS on the outer side of cork cambium differentiate to form cork. Cells on the inner side of the cork cambium differentiate to form secondary cortex. Cork is also known as PHELLEM.

The correct option is (a) True

The best explanation: In a MONOCOT stem, endodermis and cambium is absent. They don’t require an endodermis since their VASCULAR bundles are scattered. ABSENCE of cambium leads to the LACK of secondary GROWTH.

Correct answer is (d) AUTUMN wood

The EXPLANATION: Cambium is inactive in WINTER and forms fewer xylary elements that have narrow vessels and this wood has higher density and is DARKER than that of the early wood. This wood is CALLED Autumn wood.

Correct answer is (d) A cambial ring is formed in an intrafascicular cambium

Explanation: It EXISTS as a LAYER in between primary xylem and primary phloem. Intrafascicular cambium is formed when cambium cells are in between the primary xylem and phloem. Interfascicular cambium cells are medullary cells that ADJOIN intrafascicular cambium. A cambial ring is formed when interfasicular cambium cells connect intrafascicular cambium cells.

Right choice is (d) Cortex is PRESENT

To elaborate: In a monocot STEM, the VASCULAR bundles are scattered. More than ONE conjoint vascular bundle is present. Cambium is absent i.e. secondary GROWTH of vascular bundles are not possible. Cortex is absent.

Right OPTION is (a) These are the LIVING TISSUES responsible for stiffness in PLANTS

To explain: Sclerenchymatous cells are the dead cells responsible for stiffness in plants. The husk of a coconut is made of Sclerenchymatous tissue. They are of two kinds, namely, sclereids and fibers. Simple PITS are present in thickened cell walls of sclerenchyma.

Correct choice is (d) A CAMBIUM is PRESENT in between the xylem and phloem

Easiest explanation: The outermost LAYER in the root is called epidermis. The endodermis has casparian strip that avoids WATER leakage from the vascular bundles and invasion of foreign particles. Channels that connect the parenchyma cells are called plasmodermata. Cambium is absent in between the xylem and phloem.

The correct option is (a) The closing and opening of stomata is due to diffusion

Explanation: The closing and opening of stomata is due to osmosis. The factors AFFECTING stomatal MOVEMENT are light, CO2, O2, availability of water, potassium levels and temperature. Some plants like grass have dumb-belled shaped GUARD cells. Some plants like grass have dumb-belled shaped guard cells. The cells that are just BESIDE the guard cells are called subsidiary cells.

The correct option is (d) Their cell walls are regularly thickened

Easiest explanation: Collenchyma are the tissues responsible for flexibility in PLANTS and provides SUPPORT and strength for the plants. They have less INTERCELLULAR spaces in between them. They ALLOW bending of STEMS and leaves without breaking. Their cell walls are irregularly thickened.

Right choice is (d) INTERCALARY meristem helps in the increase of girth in plants

The EXPLANATION: PRIMARY meristem RISES at the early STAGE of a plant and comprises of apical and intercalary meristem. Secondary meristem rises at the later stage of a plant and comprises of later meristem. Later meristem helps in the increase of girth in plants.

Correct CHOICE is (d) ENDODERMIS are also called as wax sheath as they are rich in waxy materials

Best explanation: Epidermis is covered with a thin layer of cuticle and it bears few stomata and TRICHOMES. The hypodermis is made of collenchymatous cells and is PRESENT just below the epidermis. Cortex is made of parenchymatic cells with CONSPICUOUS intercellular spaces. Endodermis of a dicot stem is also called as starch sheath as they are rich in waxy materials.

Right CHOICE is (c) Spongy parenchyma are placed towards the adaxial epidermis

Explanation: MESOPHYLL is the portion in between adaxial and abaxial epidermis. Mesophyll cells that perform PHOTOSYNTHESIS are called PALISADE parenchyma and spongy parenchyma. Spongy parenchyma cells are placed towards the abaxial epidermis. Palisade parenchymatic cells are ELONGATED cells that are arranged parallel to each other.

The correct choice is (c) Open vascular bundles are those that have cambium in between xylem and phloem and are present in most of the monocots

The best I can explain: Epidermal appendages are outgrowth on epidermis and help in water and mineral absorption and also PREVENT water loss. All tissues that are NEITHER vascular nor epidermal tissues are called ground tissues and include parenchyma, COLLENCHYMAS and sclerenchyma. Closed vascular bundles are those that have cambium in between xylem and phloem and are present in most of the monocots. In radial vascular bundle, xylem and phloem are arranged on DIFFERENT radii.

The correct choice is (d) Xylem FIBERS are perforated and help in conduction of water to BRANCHES

Easiest EXPLANATION: Tracheids are TUBULAR structures made of dead cells without protoplasm. Xylem vessels have LIGNIFIED walls without protoplasm. Xylem parenchymatic tissues are made of thin-walled living cells and conduct water sideways. Xylem vessels are perforated and help in conduction of water to branches.

The correct answer is (b) The vascular bundles are of open type

To EXPLAIN I would say: There are more than ONE vascular bundles present in a monocot stem. The vascular bundles are of closed type. They are SCATTERED. They are surrounded by sclerenchymatous BUNDLE sheaths.

Correct choice is (a) Hypodermis

For EXPLANATION I WOULD SAY: The layer just below the EPIDERMIS in a monocot stem is called Hypodermis. Hypodermis provides additional mechanical STRENGTH to the epidermis and avoids water leakage from the stem.

Correct choice is (d) Pith in a dicot root quite larger than that of a MONO cot root

Explanation: The layer just INSIDE the endodermis in a dicot root is called pericycle. The portion between endodermis and epidermis is covered by parenchyma CELLS. SECONDARY growth INITIATES from the cells of pericycle. Pith in a mono cot root is quite larger than that of a dicot root.

The correct choice is (c) Amount of the secondary phloem PRODUCED is more than that of secondary XYLEM

The best EXPLANATION: Cells on the OUTER side of cambial ring differentiate into secondary phloem. Cells on the inner side of cambial ring differentiate into secondary xylem. Amount of the secondary phloem produced is less than that of secondary xylem. Vascular CAMBIUM is an example of Meristematic tissue.

Right CHOICE is (a) True

The BEST explanation: Vascular bundles, pericycle, pith and all other tissues inside the endodermis are combinedly called stele. The central portion of any plant cross section is called “Pith”. The portion OUTSIDE the endodermis constitutes the CORTEX.

The correct option is (B) Mesophyll is well differentiated into Palisade and spongy parenchyma cells

Easiest explanation: STOMATA is PRESENT both on abaxial and adaxial epidermis. Mesophyll is undifferentiated. VASCULAR bundles are seen in veins and mid-rib and are surrounded by thick walled BUNDLE sheath. Most of the cells are parenchyma cells.

The correct option is (a) Buliform cells that help in the CURLING of leaves are ABSENT in monocot leaf

Easiest explanation: Buliform cells that help in the curling of leaves are present in monocot leaf. Epidermis covers the entire PLANT and protects the plant from external damage. Vascular bundles in monocot STEM are NEITHER radial nor conjoint. In a monocot stem pericycle is absent.

Correct option is (a) True

Easiest EXPLANATION: CONJUNCTIVE CELLS are present only in dicot root and absent in monocot roots. These are the cells that LIE in between xylem and phloem of a dicot root. Such kind of cells are absent in monocot root.

The correct ANSWER is (d) Larger vacuoles let them BREAK easily and give MECHANICAL support

To explain I would say: Meristematic tissues are quite small which allows large number of cell division. Their cytoplasm is quite dense which means that they CONTAIN many cell ORGANELLES that help them increase their rate of respiration. Their cell wall is thin which allows them to divide easily. Vacuoles are absent in Meristematic tissues.

The CORRECT ANSWER is (d) Secondary Meristematic tissues comprises of sclerenchyma, collenchymas, parenchyma and EPIDERMIS

The best I can EXPLAIN: A cluster of cells that have a common origin and work together to ACHIEVE a specific function. A plant tissue varies from that of an animal because they vary in their functions and characters. In plant there are two types of tissues, namely, Meristematic and permanent tissues. Simple permanent tissues comprise of sclerenchyma, collenchymas, parenchyma and epidermis.

Correct answer is (d) Pith is made of vascular BUNDLES

To explain I would SAY: Xylem and phloem are vascular bundles are arranged in a ring like fashion. Hypodermis is present just below the epidermis. The vascular bundles are of OPEN type. Pith is made of parenchyma CELLS.

Correct answer is (a) Cambium

Best EXPLANATION: Secondary growth is due to lateral meristematic tissues i.e. cambium. Cambium tissues are PRIMARILY of two KINDS, namely, vascular cambium and cork cambium. Vascular cambium is RESPONSIBLE for the formation of secondary growth in vascular bundles and cork cambium is responsible for replacing the broken epidermis.

Correct answer is (d) Stomata are surrounded by a pair of kidney-shaped cells called guard cells and the inner WALLS of stomata are comparatively thinner than that of outer walls

Explanation: Epidermal TISSUE system PROVIDES protection and stops too much loss of water and comprises of EPIDERMIS, stomata and epidermal appendages. Single continuous LAYER of compactly arranged parenchymatous cells that provides complete protection are present in epidermis. Cuticle provides water proof nature for leaves and stems and stomata regulates exchange of air and water. Stomata are surrounded by a pair of kidney-shaped cells called guard cells and the inner walls of stomata are comparatively thicker than that of outer walls.

Right answer is (a) Bundle sheath cells

For explanation I WOULD say: Vascular bundles are surrounded by bundle sheath cells. Sometimes these cells contain chloroplasts and helps in carrying photosynthesis. These are tightly packed SHEATHS AROUND the VEINS of the LEAF.

The correct option is (a) True

Explanation: A layer of Meristematic tissue that develops around the cortex region is called cork CAMBIUM. Cork cambium REPLACES the broken EPIDERMIS due to secondary growth of xylem and phloem.

The correct OPTION is (a) Sclerenchymatous cells

Easy explanation: Hypodermis along with the pith of a monocot stem is MADE of sclerenchymatous cells. Also, several numbers of scattered vascular BUNDLES are SURROUNDED by sclerenchymatous cells.

Correct answer is (a) True

Best explanation: Secondary growth refers to the girthwise growth. LATERAL MERISTEMATIC tissues are responsible for secondary growth. A monocot can’t show secondary growth WHEREAS DICOT EXHIBIT secondary growth.

Correct option is (a) True

For EXPLANATION: The branch of BIOLOGY that deals with the internal structure and PARTS of an ORGANISM is called “Anatomy”. Plant anatomy deals with internal TISSUES and cells present in a plant.

The correct option is (C) The intercellular GAPS in Parenchyma are negligible

Easy EXPLANATION: The PACKING tissues in plants that stores food, nutrients and water are called Parenchyma. Parenchyma with chlorophyll is called chlorenchyma and parenchyma with air is called aerenchyma. The intercellular gaps in Parenchyma are large. Aerenchyma is mostly present in AQUATIC plants and chlorenchyma is present in leaves.

Correct choice is (a) PITH

Best explanation: The central portion of the stem or a root or a leaf is called the pith. Cortex is the region outside the ENDODERMIS. Vascular BUNDLES are those that help in TRANSPORTATION of food and water. Ground tissue is that region of a PLANT excluding vascular bundles and epidermis.

The correct answer is (d) Phloem fibers are living cells with extremely THICK cell walls and PROVIDE mechanical strength

The best I can explain: SIEVE tubes are tubular cells with perforated walls with large vacuoles, peripheral cytoplasm and without nucleus. Companion cells are specialized parenchyma cells that HELP in regulation of metabolic activities. Phloem parenchyma cells are elongated cylindrical cells that support sieve tubes. Phloem fibers are DEAD cells with extremely thick cell walls and provide mechanical strength.

Right answer is (a) True

For explanation I would say: Vascular cylinder comprises of the PERICYCLE, XYLEM, phloem and pith. Cortex includes the PORTION exterior to the ENDODERMIS and comprising of parenchyma CELLS, hypodermis and epidermis.