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?

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.

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.

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.

A potted plant having straight parts A and B was placed horizontally on its side as shown in Figure (i). After a few days it was observed that the parts A and B of the plant acquire new positions as shown:

(a) Name the phenomenon exhibited by the position of plant parts A and B in Figure (ii)

(b) Name the stimulus (other than sunlight) which causes plant part A to grow and bend upwards, and plant part B to bend downwards.