Q31. The arrangement of leaves on a stem or branch is called:
a) Venation
b) Vernation
c) Phyllotaxy
d) Placentation
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Correct Answer: c) Phyllotaxy
Explanation: Phyllotaxy refers to the pattern or arrangement of leaves on the stem or branch. There are mainly three types: alternate, opposite, and whorled. Venation is arrangement of veins in a leaf. Vernation is leaf arrangement in bud. Placentation is ovule arrangement in ovary.
Q32. Reticulate venation is characteristic of leaves of:
a) Monocots
b) Dicots
c) Pteridophytes
d) Gymnosperms
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Correct Answer: b) Dicots
Explanation: Reticulate (net-like) venation is a characteristic feature of dicotyledonous leaves. In reticulate venation, veins and veinlets are irregularly distributed, forming a network or reticulum throughout the lamina. Parallel venation is typical of monocot leaves, where veins run parallel to each other from base to apex. Pteridophytes and gymnosperms have different types of venation patterns.
Q33. Parallel venation is characteristic of leaves of:
a) Dicots
b) Monocots
c) Bryophytes
d) Gymnosperms
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Correct Answer: b) Monocots
Explanation: Parallel venation is a characteristic feature of monocotyledonous leaves. In parallel venation, veins run parallel to each other from the base to the apex of the leaf blade (lamina). Dicots have reticulate venation. Bryophytes and gymnosperms are not primarily categorized by leaf venation in this way.
Q34. When the lamina is completely divided into leaflets, the leaf is called:
a) Simple leaf
b) Compound leaf
c) Pinnately compound leaf
d) Palmately compound leaf
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Correct Answer: b) Compound leaf
Explanation: When the leaf lamina is completely divided into distinct leaflets, it is called a compound leaf. In a simple leaf, the lamina is entire or incised, but the incisions do not reach up to the midrib, and it does not divide into leaflets. Pinnately and palmately compound are types of compound leaves, distinguished by leaflet arrangement.
Q35. In which type of compound leaf, the leaflets are attached to a common point at the tip of petiole?
a) Pinnately compound leaf
b) Palmately compound leaf
c) Simple leaf
d) Decompound leaf
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Correct Answer: b) Palmately compound leaf
Explanation: In a palmately compound leaf, the leaflets are attached at a common point, which is the tip of the petiole, radiating out like fingers from the palm, e.g., silk cotton. In a pinnately compound leaf, leaflets are attached laterally on a common axis (rachis) resembling a feather, e.g., neem. Simple leaf has undivided lamina, and decompound leaf is further divided.
Q36. In a pinnately compound leaf, the leaflets are attached to:
a) Petiole
b) Rachis
c) Petiolule
d) Pulvinus
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Correct Answer: b) Rachis
Explanation: In a pinnately compound leaf, the leaflets are attached laterally on a common axis called the rachis, which represents the midrib of the compound leaf, e.g., neem and rose. Petiole is the stalk of the leaf, petiolule is stalk of leaflet, and pulvinus is swollen leaf base.
Q37. The swollen leaf base present in leguminous plants is called:
a) Lamina
b) Pulvinus
c) Rachis
d) Petiole
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Correct Answer: b) Pulvinus
Explanation: Pulvinus is a swollen leaf base found in leguminous plants and some others. It helps in sleep movements of leaves (nyctinastic movements) and also in rapid leaf movements in sensitive plants. Lamina is leaf blade, rachis is axis of pinnately compound leaf, and petiole is leaf stalk.
Q38. Which type of inflorescence is characterized by a main axis that continues to grow indefinitely, and flowers are borne laterally in acropetal succession?
a) Raceme
b) Cyme
c) Umbel
d) Capitulum
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Correct Answer: a) Raceme
Explanation: Raceme is a type of indeterminate inflorescence where the main axis (peduncle) continues to grow indefinitely, and flowers are borne laterally along the axis in acropetal succession (younger flowers towards the apex, older towards the base). Cyme is determinate (main axis stops growing), umbel has flowers arising from a common point, and capitulum is head inflorescence.
Q39. In which type of inflorescence, the main axis terminates in a flower, hence having limited growth, and flowers are borne in basipetal succession?
a) Raceme
b) Cyme
c) Spike
d) Corymb
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Correct Answer: b) Cyme
Explanation: Cyme is a type of determinate inflorescence where the main axis terminates in a flower, thus limiting its growth. Flowers are borne in basipetal succession (older flowers towards the apex, younger towards the base). Raceme is indeterminate, spike is a type of raceme with sessile flowers, and corymb is a raceme where lower flowers have longer pedicels bringing all flowers to same level.
Q40. Hypogynous flower is characterized by:
a) Gynoecium occupying the highest position and other floral parts below it
b) Gynoecium occupying the lowest position and other floral parts above it
c) Gynoecium and other floral parts at the same level
d) Gynoecium surrounding other floral parts
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Correct Answer: a) Gynoecium occupying the highest position and other floral parts below it
Explanation: In a hypogynous flower, the gynoecium (ovary) occupies the highest position on the thalamus, and other floral parts (sepals, petals, stamens) arise below it. The ovary in this case is said to be superior, e.g., mustard, china rose, and brinjal. Epigynous has ovary inferior, and perigynous has ovary half-inferior.