Which of the following phenomena might have influenced the evolution of organisms? 1. Continental drift 2. Glacial cycles Select the correct answer using the code given below.

Both continental drift and glacial cycles have profoundly influenced the evolution of organisms:

1. Continental drift: The slow movement of Earth's continents over millions of years has dramatically altered global climates, ocean currents, and the distribution of landmasses. This has led to:

Geographical isolation: Separating populations that were once connected, leading to allopatric speciation as isolated groups evolve independently. For example, the distribution of marsupials in Australia and South America is a result of continental drift. New environmental conditions: As continents moved into different climatic zones, organisms had to adapt to new temperatures, rainfall patterns, and habitats, driving evolutionary change. Formation and destruction of barriers: The opening and closing of oceans and land bridges influenced migration routes and gene flow. 2. Glacial cycles: Recurring periods of extensive glaciation (ice ages) followed by warmer interglacial periods have occurred over geological time, especially in the Quaternary period. These cycles caused:

Drastic climate changes: Leading to shifts in vegetation zones and habitat availability. Sea-level fluctuations: Lowering sea levels during glaciations exposed land bridges (e.g., Beringia), facilitating species migrations, while rising sea levels during interglacials isolated populations on islands. Selective pressures: Organisms faced intense selective pressures to adapt to colder temperatures, reduced food availability, and altered landscapes, leading to evolutionary adaptations or extinctions. Thus, both phenomena have played crucial roles in shaping the diversity and distribution of life on Earth.