In Lamarck’s view, the key of organic evolution is that each progeny

The correct option is "characters acquired by parental generation are inherited".

Jean-Baptiste Lamarck, a French naturalist, proposed one of the earliest theories of organic evolution, known as Lamarckism or the theory of inheritance of acquired characters. According to Lamarck's view, evolution is driven by the interaction of organisms with their environment.

Lamarck's theory is built on two primary principles:
1. Use and Disuse: Organs or body parts that are used extensively by an organism to cope with environmental needs become stronger, larger, and more developed. Conversely, organs that are not used deteriorate and eventually disappear over generations.
2. Inheritance of Acquired Characters: The structural or physiological changes (acquired characters) developed by an individual during its lifetime due to use, disuse, or environmental influence are passed on to its offspring (progeny).

Therefore, in Lamarck’s view of organic evolution, the key mechanism is that each progeny inherits the characters that were acquired by the parental generation during their lifetime.