Pick the correct match

The correct option is: Parthenium hysterophorus – a threat to biodiversity

Let us evaluate each match to understand why this pair is correct and why the other options are incorrect:

1. Parthenium hysterophorus – a threat to biodiversity:
Parthenium hysterophorus, commonly known as carrot grass or congress grass, is an invasive alien weed species in many countries including India. It grows aggressively, competes with native vegetation for resources, and secretes allelopathic chemicals that inhibit the growth of nearby plants. Thus, it poses a significant threat to native plant species and overall local biodiversity, making this a correct match.

2. Stratification – Population:
Stratification is the vertical distribution of different species occupying different levels in a biotic community (such as trees in the top canopy, shrubs in the middle, and herbs/grasses at the bottom). Therefore, stratification is a structural characteristic of an ecological community, not a population.

3. Aerenchyma – Opuntia:
Aerenchyma is a spongy tissue containing large air spaces commonly found in aquatic plants (hydrophytes) to facilitate buoyancy and gaseous exchange. Opuntia is a xerophytic plant (cactus) adapted to dry, arid conditions, characterized by anatomical features like thick cuticles, sunken stomata, and water-storing tissues (parenchyma), not aerenchyma.

4. Age Pyramid – Biome:
An age pyramid is a graphical representation of the distribution of various age groups within a specific population (often categorized as pre-reproductive, reproductive, and post-reproductive). It is a key attribute used to study population dynamics, not a biome (which is a large regional ecological unit characterized by major vegetation types and climate).