Concept:Organic evolution is the gradual change in living organisms over successive generations.
Explanation:The phrase "changes of living organisms over generations" is the standard definition of evolution.
Evolution occurs when the genetic composition of a population changes from one generation to the next.
These genetic changes accumulate over time, leading to new traits and sometimes entirely new species.
Organic evolution applies to all living organisms, from simple bacteria to complex plants and animals.
Option A (human evolution) is incorrect because it deals only with the ancestry of humans, not all organisms.
Option C (physical evolution) is incorrect because it focuses narrowly on structural body changes rather than the total evolutionary process.
Option D (chemical evolution) is incorrect because it describes events before life existed, such as the formation of organic molecules from inorganic matter.
Hence, the correct term that matches the description in the question is organic evolution.
Answer:B. Organic evolution