On the Galapagos Islands, Darwin observed that the characteristics of many animals and plants:

• A. remained unchanged over generations
• B. were identical to those found on the South American mainland
• C. varied from island to island, suggesting adaptation to different environments
• D. were determined solely by the climate of the islands

Answer: (C)

Verified step by step guidance

1. Understand the context of the problem: Charles Darwin's observations on the Galapagos Islands were foundational to his theory of natural selection. He noticed differences in species that suggested adaptation to their specific environments.
2. Focus on the key observation: Darwin observed that the characteristics of animals and plants varied from island to island. This variation was significant because it indicated that species were not static but could change over time in response to environmental pressures.
3. Relate the observation to adaptation: The differences in traits among species on different islands suggested that these traits were adaptations to the unique conditions of each island, such as food availability, predators, or climate.
4. Eliminate incorrect options: Traits that 'remained unchanged over generations' or were 'identical to those found on the South American mainland' do not align with Darwin's observations. Similarly, traits being 'determined solely by the climate' oversimplifies the role of natural selection and adaptation.
5. Conclude with the correct interpretation: Darwin's observations supported the idea that species varied from island to island, which was evidence of adaptation to different environments, a key concept in evolutionary biology.