The gradual cumulative, adaptive and heritable changes in an organism over a long period of time resulting in new species is called

1. Analyze the question The question describes changes that are:

• gradual (slow, over a long time)
• cumulative (build up over generations)
• adaptive (help the organism survive in its environment)
• heritable (passed from parents to offspring)

and these changes eventually result in new species. We need the term for this process.

2. Explain the concept Organic evolution is the gradual change in living organisms over many generations, through inherited variations acted on by natural selection, leading to the formation of new species. Examples include the development of modern horses from smaller ancestors and the evolution of different finch species in the Galápagos Islands.

3. Go through the options

• A. Adaptation: This is a feature or change that helps an organism survive in its environment (such as a camel's hump). It is only one part of the process and does not by itself produce new species.
• B. Survival: This just means staying alive. It is not a process that produces new species.
• C. Organic evolution: This matches every part of the description: gradual, cumulative, adaptive, heritable, and leading to new species.
• D. Interspecific competition: This is competition between different species for resources such as food or space. It has nothing to do with the definition given.

4. Answer The correct option is C. organic evolution.

5. Exam tip Look for the keywords in the question: "gradual", "long period", "heritable" and "new species" almost always point to evolution. Remember: adaptation is a feature, evolution is the long-term process.