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Coordination in plants
5. Which of the following plant 8. A student applied fertilizer
processes are regulated by specifically to one side of each maize
gibberellins in plants? plant. Over several days, plant root
growth and overall growth improved
(a) Leaf senescence and detach from significantly. Which phenomenon
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plant
best explains the roots’ growth
(b) Stem elongation and seed response?
germination (a) Positive phototropism, with
(c) Fruit ripening and induce rotting auxins directing growth toward
(d) Root and shoot growth in the light.
direction of light. (b) Negative geotropism, with auxins
causing upward shoot growth.
6. What is the role of the hormone (c) Positive chemotropism, with
ethylene in plant coordination? auxins accumulating in response
(a) Promotes cell division to chemical stimuli.
(b) Stimulates fruit ripening (d) Thigmotropism, with cytokinins
promoting growth toward
(c) Inhibits seed germination mechanical contact.
(d) Increases root growth 9. A Form Three student noticed that
the flowers in the garden were
7. A plant is placed in a room where the
only light source comes from a small closed during the early morning and
evening but opened during the day.
window on the right side. After a few Which phenomenon best explains
days, you notice the plant is growing the flowers’ behaviour, and which
towards the window. Which process hormone is involved?
and hormone is responsible for the
plant’s growth towards the light? (a) The plant exhibits phototropism,
with auxins causing flowers to
(a) Geotropism; Auxins accumulate open and close subsequently with
on the illuminated part of the varied light intensity
shoot.
(b) Phototropism; Auxins accumulate (b) The plant exhibits gravitropism,
on the shaded side of the plant. with ethylene and auxins causing
the gravitational force to close
(c) Phototropism; Auxins the flowers when the light is dim.
concentrated on the terminal part
of the shoot. (c) The plant is exhibiting
(d) Thigmotropism; Auxins cause the photonasty, with ethylene and
auxins influencing the opening
plant to bend towards the light. and closing of flowers in response
to light.
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BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 17 KAMISHNA 23/10/2025 11:52:31
BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 17
KAMISHNA
