Apart from genetic variation, which type of isolation is stated to lead to speciation?

1. Genetic variation is the main cause of new species forming from older ones. 2. The text adds that geographical and reproductive changes also contribute. 3. When populations get separated geographically or reproductively, gene flow stops. 4. This isolation lets differences accumulate, leading to speciation. 5. So the answer is geographical or reproductive isolation. 6. Trap (thermal or magnetic): these are not mentioned as isolating factors here. 7. Trap (chemical or electrical): these play no stated role in speciation. 8. Trap (acoustic or optical): these are not the isolation types described. 9. Hence geographical or reproductive isolation is correct. _Source: Balbharati (Maharashtra Board) Class 10 Science & Technology Part 2, Ch 1 "Heredity and Evolution", p.18_