Read the following statements and choose the correct option:

1. The introduction of invasive alien species can lead to the displacement of native species.

2. Water hyacinth (Eichhornia) is an invasive plant that disrupts the ecological balance in water bodies.

3. The African catfish (Clarias gariepinus) was introduced legally for aquaculture purposes.

4. The Nile perch's introduction to Lake Victoria had no significant impact on the lake's native fish species.

 Statements 1 and 2 are correct.

The correct answer is Option (3) -  Statements 1 and 2 are correct.

Alien species invasions occur when non-native species are introduced, either intentionally or unintentionally, to a new ecosystem. In some cases, these alien species become invasive and have detrimental effects on the native species and ecosystem. For instance, the introduction of the Nile perch into Lake Victoria in east Africa resulted in the extinction of more than 200 species of cichlid fish that were unique to the lake's ecosystem.

Similarly, invasive weed species like carrot grass (Parthenium), Lantana, and water hyacinth (Eichhornia) pose environmental damage and threats to native species in various regions. These invasive plants can outcompete native vegetation, disrupt ecological balance, and reduce biodiversity.

Additionally, the illegal introduction of the African catfish Clarias gariepinus for aquaculture purposes poses a threat to the indigenous catfish species in rivers, potentially leading to competition and displacement of native species.

Invasive alien species can have severe consequences for the biodiversity and ecological integrity of ecosystems, making their management and control crucial to preserve native species and maintain ecosystem balance.