Q.A rubber band stretches and reverts back to its original position. Bubble gum stretches, but it would not return to its original position. Is there any difference between the two processes? Discuss it with respect to plant growth (Hint: Elasticity (reversible); Plasticity (irreversible)).

Yes, there is an important difference between the two, and it maps directly onto the distinction between elasticity and plasticity in plant growth. The rubber band's behaviour — stretching and then reverting fully back to its original shape — is elastic, a reversible change. The bubble gum's behaviour — stretching and then staying stretched, never returning to its original form — is plastic, an irreversible change. In plant growth, this same irreversibility is central: true growth is itself defined as an irreversible, permanent increase in size, and plasticity in development likewise means a lasting change i …

There is indeed a fundamental difference between the two behaviours described. When a rubber band is stretched, it returns to its original position once released — this reversible behaviour is elasticity. When bubble gum is stretched, it stays stretched and does not spring back — this permanent, non-reversible behaviour is plasticity.

This distinction connects directly to how growth itself is defined in plants. Growth is described as an irreversible, permanent increase in size of an organ, its parts, or an individual cell — precisely because the change cannot be undone. This is exactly why a temporary change, such as a dry piece of wood swelling in water and shrinking again once it dries, is not counted as true growth: it is reversible, like the rubber band, rather than a genuine, lasting increase. …

Method: Applying the Elasticity-vs-Plasticity Test to a Biological Change

Use this method for any question that gives two everyday analogies and asks you to map them onto a biological growth concept.

Steps

Step 1: Test reversibility for each analogy

Ask of each example given: after the stretching/change stops, does it return to its original state (reversible) or stay changed (irreversible)? This single test — not appearance or magnitude — is what separates elasticity from plasticity.

Step 2: Name the property, don't just describe the behaviour

Reversible stretch-and-return = elasticity. Permanent, non-reverting change = plasticity. State the term, not just "it goes back"/"it stays."

Step 3: Connect the test to the definition of true growth …