P and Q are two types of plants having weak stems which cannot stand upright on their own. The plants P and Q have organs R and S respectively which can grow towards any support which they happen to touch and wind around that support. It is- observed that organ R originates from the leaves of the plant whereas organ S originates directly from the stem of the plant.

(a) What is (i) R, and (ii) S?

(b) What is the name of growth movement exhibited by the organs R and S?

(c) Name the stimulus involved in this case.

(d) State whether the behaviour of organs R and S is a tropic movement or a nastic movement.

(e) Name one plant like P and another plant like Q.

There are three plants A, B and C. The flowers of plant A open their petals in bright light during the day but close them when it gets dark at night. On the other hand, the flowers of plant B open their petals at night but close them during the day when there is bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.

(a) Name the phenomenon shown by the flowers of (i) plant A, and (ii) plant B.

(b) Name one flower each which behaves like the flower of (i) plant A, and (ii) plant B.

(c) Name the phenomenon exhibited by the leaves of plant C.

(d) Name a plant whose leaves behave like those of plant C.

(e) Which plant/plants exhibit the phenomenon based on growth movements?

While conducting experiments to study the effect of various stimuli on the plants, it was observed that the roots of a plant X grow and bend towards two stimuli A and B but bend away from a third stimulus C. The stem of the plant X, however, bends away from stimuli A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to too much weight of the earth. Keeping these points in mind, answer the following questions:

(a) What could stimulus A be?

(b) Name the stimulus B.

(c) What could stimulus C be?

(d) The branches of a fallen tree in a forest grow straight up in response to two stimuli. What could be these two stimuli out of A, B and C? Also name these two stimuli.

The top part A of the flask-shaped reproductive organ X in the flower of a plant secretes a surgery substance into its lower part B which goes towards the bottom part C of the flask-shaped organ. When a tiny grain D coming from the top part E of another reproductive organ Y in the flower falls on part A, it grows a long tube F through the organ X in response to the sugary substance and reaches the bottom part C of flask � shaped organ to carry out fertilisation.

(a) What is (i) organ X, and (ii) organ Y, inside the flower?

(b) Name parts (i) A (ii) B, and (iii) C, of flask-shaped organ.

(c) Name (i) grain D, and (ii) part E of organ Y.

(d) Name the tube F.

(e) What is the phenomenon of growing a long tube in response to a sugary substance in the process of fertilization in a flower known as?

P, Q, R and S are four major types of phytohormones. P is a phytohormone which functions mainly as a growth inhibitor. It promotes the wilting and falling of leaves. Q, R and S are phytohormones which all promote growth of plants in various ways. Q is responsible for the phenomenon of phototropism in plants. R is involved mainly in shoot extensions. The phytohormone S helps in breaking the dormancy of seeds and buds. What are P, Q, R and S? Give one reason each for your choice.