Answer: A. Mineral deposits

Explanation: Phytoliths are microscopic mineral deposits formed in plant tissues. They are composed mainly of silica and provide structural support as well as serve as a defense mechanism against herbivory.

Answer: B. Rosette

Explanation: In rhubarb, calcium oxalate crystals typically form in a rosette pattern. These crystals can be observed microscopically and are important for plant defense and structural integrity.

Answer: A. Vanillin

Explanation: 4-hydroxy-3-methoxy-benzaldehyde, commonly known as vanillin, is the primary component responsible for the characteristic aroma and flavor of vanilla. It is widely used in the food and fragrance industries.

Answer: A. Flavonoids

Explanation: Vitamin P refers to a group of flavonoids, which are bioactive compounds known for their antioxidant properties. They contribute to vascular health and play a role in stabilizing capillary walls.

Answer: A. Bark of Taxus baccata

Explanation: Taxol, a potent anticancer agent, is extracted from the bark of Taxus baccata. Its discovery has led to the development of new therapies for the treatment of various cancers.

Answer: C. (Number of stomata per mm² × 100) / (Number of epidermal cells per mm² + Number of stomata per mm²)

Explanation: The stomatal index is calculated as the ratio of the number of stomata to the total number of epidermal cells plus stomata, multiplied by 100. It provides a measure of the relative density of stomata on a leaf surface.

Answer: C. Histidine

Explanation: Imidazole-containing alkaloids are biosynthesized from histidine. The imidazole ring in histidine serves as the structural foundation for these compounds, influencing their biological activity and medicinal applications.

Answer: C. Harmaline

Explanation: β-carbolines such as harmaline are naturally occurring compounds found in certain plants. Harmaline exhibits psychoactive properties and is used both in traditional medicine and as a research tool to study neural pathways.

Answer: D. Shankhapushpi

Explanation: Convolvulus pluricaulis, known as Shankhapushpi, is a traditional Ayurvedic herb reputed for its nootropic properties, often used to enhance memory and cognitive function.

Answer: B. Abscisic acid

Explanation: Abscisic acid is the plant hormone responsible for inducing seed dormancy. It inhibits germination until environmental conditions are favorable, thus playing a crucial role in plant survival.

Answer: B. Aromatic non-carbohydrate polymer

Explanation: Lignin is a complex aromatic polymer found in plant cell walls. It is not a carbohydrate and provides rigidity and resistance to microbial degradation in plants.

Answer: C. Tannins

Explanation: Tannins are high-molecular-weight flavonoid polymers that are water-soluble. They are known for their astringency and ability to precipitate proteins, which underlies their use in tanning leather.

Answer: B. Linum usitatissimum

Explanation: Linum usitatissimum, commonly known as flaxseed, is rich in lignans. These polyphenolic compounds have antioxidant properties and are linked to various health benefits, including hormone modulation.

Answer: A. Monocot stem

Explanation: Monocot stems typically do not show a clear differentiation between pith and cortex.

Answer: C. 2-ethyl pyrroline

Explanation: The characteristic rice aroma arises from 2-acetyl-1-pyrroline, not 2-ethyl pyrroline.

Answer: B. Boswellia serrate

Explanation: Boswellia serrata (or serrate) is the source of Indian frankincense.

Answer: A. Biflavons, Diterpenes

Explanation: Ginkgo folium contains biflavones and diterpenes as active agents.

Answer: B. Ornithine

Explanation: Ornithine is the precursor in the biosynthesis of tropane alkaloids.

Answer: A. Frontal lobe

Explanation: Primary sensory cortex resides in the postcentral gyrus of the parietal lobe, not frontal.

Answer: A. Triterpenoid aldehyde

Explanation: Gossypol is classified as a triterpenoid aldehyde.