In the following statements, tick ‘T’ against those which are true, and ‘F’
against those which are false.
(a) Sound cannot travel in vacuum. (T/F)
(b) The number of oscillations per second of a vibrating object is called
its time period. (T/F)
(c) If the amplitude of vibration is large, sound is feeble. (T/F)
(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)
(e) The lower the frequency of vibration, the higher is the pitch. (T/F)
(f) Unwanted or unpleasant sound is termed as music. (T/F)
(g) Noise pollution may cause partial hearing impairment. (T/F)
Give reasons for
(a) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.
(b) Intercellular spaces are absent in sclerenchymatous tissues.
(c) We get a crunchy and granular feeling, when we chew pear fruit.
(d) Branches of a tree move and bend freely in high wind velocity.
(e) It is difficult to pull out the husk of a coconut tree.
Describe the structure and function of different types of epithelial tissues. Draw diagram of each type of epithelial tissue.
Fill in the blanks
(a) ———are forms of complex tissue.
(b) ———have guard cells.
(c) Cells of cork contain a chemical called———
(d) Husk of coconut is made of ———tissue.
(e) ———gives flexibility in plants.
(f) ———and———are both conducting tissues.
(g) Xylem transports———and———from soil.
(h) Phloem transport———from———to other parts of the plant
Fill in the blanks
(a) Cork cells possesses———on their walls that makes it impervious to gases and water.
(b) ——— have tubular cells with perforated walls and are living in nature.
(c) Bone possesses a hard matrix composed of———and ———.