This is the correct answer as both statements a and b are correct. The direction of nastic movement is not determined by the direction in which the stimulus is applied. Nastic movements are generally exhibited by the flat organs of plants like leaves or petals of flowers.

These are bristle-like structures found on an earthworm's body.

This option is correct because the locomotory organ of class Sarcodina is pseudopodia.

The body of an earthworm is soft as it does not have bones. It moves by the peristaltic action of muscles and affixes itself to the ground with the help of large number of tiny bristles. Also, its body secretes a slimy substance to help in the movement.

Breast muscles help a cockroach in flying. 

Closing up of leaves of a sensitive plant on touching with an object is nastic movement, not tropic movement.

The locomotory organs of the given organisms are: Amoeba - Pseudopodia Hydra - Tentacles Paramecium - Cilia

The drooping or folding of legume leaves in the dark is called nyctinasty.

This is the correct option. Growth of pollen towards the ovule - Chemotropism Winding of tendrills towards the support - Positive thigmotropism This is a wrong option as 'b' is correctly matched.  Bending of roots towards water - Positive hydrotropism Winding of tendrills towards the support - Positive thigmotropism

This is the correct option. Folding of leaves of Mimosa pudica plant on touching is thigmonasty.

Cockroach is an animal with three pairs of legs. It can walk with the help of its legs. It can climb up the walls and can also undergo short flights due to the presence of wings, which are attached to its breast.

Cockroaches have 3 pairs of legs.

When light is incident on one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot, which is away from light. Thus, the plant appears to bend towards light.

Thigmotropism is shown by tendrils in response to touch.

Tropism means movement in response to stimuli. Plants show movement in response to stimuli.  Chemotropism is the movement of plants in response to chemicals. It can be away or towards chemicals, e.g. growth of pollen tubes towards ovules in response to some chemical substances that are secreted by ovules to attract pollen tubes.