IGCSE Biology Paper-3: Specimen Questions with Answers 319 - 321 of 358
Passage
Fig. is a drawing of a piece of plant tissue.
Question 319 (4 of 4 Based on Passage)
Explanation
Vessel Element of Xylem
Xylem Vessels: Vessels are rows of elongated tube-like cells, placed end to end with their end walls dissolved. Vessels usually do not occur in Pteridophyta and Gymnospermous xylems but in Pteridium, Selaginella (both Pteridophytes) and in Ephedra, Gnetum (Gymnosperms) vessels are present. In Angiosperms vessels are always present (Except Lotus, Wintera, Trochodendron)
Passage
Leaves are made of tissues.
Question 320 (1 of 6 Based on Passage)
Explanation
Relative Humidity
As the relative humidity of the air surrounding the plant rises the transpiration rate falls. It is easier for water to evaporate into dryer air than into more saturated air. Wind and air movement: Increased movement of the air around a plant will result in a higher transpiration rate.
Question 321 (2 of 6 Based on Passage)
Explanation
Tissue
A group of structurally similar or dissimilar cells that perform a common function and have a common origin is called a tissue. A plant is made up of different kinds of tissues. The complex tissues are, however, composed of different kinds of cells and they perform different types of functions. Each tissue has a specific function to perform and different types of tissues of a plant body function in co-ordination with one another.