Describe the various types of trichomes found in plants with example(s) of each

The stage micrometer has a precisely known scale (e.g., 1 mm divided into 100 divisions, so each division is $0.01 \text{ mm}$ or $10 \mu\text{m}$).

• Example: If 50 divisions of the eyepiece micrometer coincide with 10 divisions of the stage micrometer, and each stage micrometer division is $0.01 \text{ mm}$ ($10 \mu\text{m}$): $$\text{Value of 1 EMD} = \frac{10 \text{ SMD} \times 0.01 \text{ mm/SMD}}{50 \text{ EMD}} = \frac{0.1 \text{ mm}}{50} = \boxed{0.002 \text{ mm} \text{ or } 2 \mu\text{m}}$$

6. Explain how to prepare a drug sample for microscopical examination

The preparation method depends on whether the drug is organized (e.g., leaf, root) or unorganized (e.g., gum, resin) and its physical state (whole, cut, or powdered).

Cut very thin transverse or longitudinal sections using a sharp razor blade or microtome. The sections should be thin enough for light to pass through.

Place a small amount of the powder (a few milligrams) on a clean microscope slide.

Common media include: * Water: For general observation. * Glycerin: To prevent drying and improve clarity. * Chloral hydrate solution: To clear plant tissues by dissolving starch and chlorophyll, making internal structures more visible. Gentle heating may be required. * Phloroglucinol and concentrated HCl: To stain lignified tissues red. * Sudan III or IV: To stain oily or fatty substances red/orange.