Correct Option
The correct option is (c) 1 and 3 only.
Explanation
In biology, a distinction is drawn between movement and locomotion. Locomotion refers to the displacement of an entire organism from one place to another, whereas movement refers to a change in position of a part of the body or the internal transport of substances. While plants are generally sessile (stationary), they exhibit various forms of internal and external movements.
Statement-wise Analysis
- Statement 1 is Correct: Plants are anchored to the substratum (soil) by their roots. Consequently, they do not exhibit locomotion, which is the voluntary movement of an organism from one place to another. They remain fixed in one location throughout their life cycle.
- Statement 2 is Incorrect: Plants exhibit significant internal movement. Water and minerals absorbed by roots are transported upwards to leaves via the xylem, and food synthesized in leaves is transported to other parts via the phloem. This internal transport is a critical physiological form of movement.
- Statement 3 is Correct: The opening and closing of flowers are examples of nastic movements (e.g., photonasty or thermonasty). These are non-directional movements in response to environmental stimuli such as light or temperature. Therefore, this constitutes a valid form of movement in plants.
Key Takeaway: Plants do not show locomotion (displacement of the whole body), but they exhibit movements such as the internal transport of nutrients and the curvature or opening/closing of organs (tropic and nastic movements).