Question

Animals show locomotion, but plants do not. What is the reason for this?
A. Plants are autotrophs
B. Plants are heterotrophs
C. Plants have organs of defence.
D. None of these.

Answer 1

Hint: Movement of the whole body from one place to the other is referred to as locomotion. But movement includes the change in size, shape and direction of the body part with respect to its body axis. In locomotion external body parts are involved but internal and external body parts are involved in movement.

Complete answer:
All living beings have the capability of movement. Movement results in the change of position, place or posture. For all living beings movement is essential. Plants show only movement while animals show both locomotion and movement. Plants show movement to protect themselves from danger, to obtain nutrients, water, soil etc. Animals show locomotion and movement to escape from danger, to capture and seek food etc.
An autotroph is an organism that produces complex organic compounds from simple substances such as carbon dioxide using carbon. They generally use energy from inorganic chemical reactions or light. Autotroph does not exhibit locomotion. Since plants are autotrophs they do not show locomotion.

Hence, the correct answer is option (A).

Note: Movements in plant parts can be broadly categorized into two categories:
Tropic movements:
Geotropism – Growth movements that are induced by gravity.
Phototropism – Bending of plants towards the light.
Hydrotropism – Movement of plants towards the water.
Thigmotropism – Response of plants due to the stimulus of touch.

Nastic movements:
These are rapid movements of the plant organs in response to the stimulus that results from alterations in the cell volume in specialized motor organs known as pulvinus.