SolveItNCERT · CBSE Boards

NCERT Exemplar · Class 9 Science Tissues

55 questions · 55 still being checked

Short Answer Questions 44–48 (part 5 of 6)

  1. Exercise 44

    Water hyacinth float on water surface. Explain.

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    Hint— Due to aerenchyma present in the swollen petiole.
    Water hyacinth is aquatic; its parenchyma cells enclose large air cavities (aerenchyma) instead of packing tightly.Trapped air \(\displaystyle \Rightarrow\) lowers the plant's overall density \(\displaystyle \Rightarrow\) it floats. Answer: Aerenchyma (air-filled parenchyma) makes the plant buoyant, so it floats on water.

  2. Exercise 45

    Which structure protects the plant body against the invasion of parasites?

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    Hint- Epidermis having thick cuticle and waxy substances to prevent the invasion of parasites.
    Epidermis — the single outer layer of cells on the plant's aerial parts — secretes a waxy cuticle. Waxy cuticle \(\displaystyle \Rightarrow\) impervious to water and gases \(\displaystyle \Rightarrow\) blocks invasion by parasitic fungi. Answer: Epidermis, sealed by its waxy cuticle, protects the plant against parasite invasion.

  3. Exercise 46

    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 ———.

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (a)
    suberin (b) sieve tubes (c) calcium and phosphorus
    (a)
    suberin — waterproofs and gas-seals the cork wall.
    (b)
    Sieve tubes (phloem) — living, tube-like cells with perforated end walls for food transport.
    (c)
    calcium and phosphorus compounds — give bone its hard, load-bearing matrix.
    Answer: (a) suberin (b) sieve tubes (c) calcium and phosphorus.

  4. Exercise 47

    Why is epidermis important for the plants?

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    Hint—Epidermis is important for plants due to the following reasons (i) it gives protection (ii) helps in gaseous exchange (iii) checks water loss (iv) root hairs arising from epidermis helps in absorption of water and minerals.
    Waxy cuticle on aerial parts \(\displaystyle \Rightarrow\) cuts water loss, guards against mechanical injury and fungal attack. Leaf stomata (guard-cell pores) handle gas exchange and transpiration; root epidermis instead grows water-absorbing root hairs. Answer: Epidermis protects the plant (cuticle), reduces water loss, carries out gas exchange (stomata) and absorption (root hairs).

  5. Exercise 48

    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.

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (a)
    Xylem and phloem (b) Stomata (c) Suberin (d) Sclerenchyma (e) Collenchyma (f) Xylem; phloem (g) Water; minerals (h) food; leaf
    (a)
    Xylem, phloem — complex tissues.
    (b)
    Stomata — pores flanked by guard cells.
    (c)
    suberin.
    (d)
    sclerenchyma — dead, thick-walled fibres.
    (e)
    Collenchyma — flexible, unevenly thickened walls.
    (f)
    Xylem, phloem — conducting tissues.
    (g)
    water, minerals — drawn up from soil.
    (h)
    food; leaves — carried to the rest of the plant.
    Answer: (a) xylem/phloem (b) stomata (c) suberin (d) sclerenchyma (e) collenchyma (f) xylem/phloem (g) water/minerals (h) food from leaves.