Cuvier, lamarck, and erasmus darwin all shared an idea of evolution; however, they all lacked:
a. the longevity necessary for evolution to take place.
b. a basic understanding of inheritance.
c. an understanding of variation.
d. a mechanism for evolution.

D- a mechanism for evolution

Explanation: The mechanism for evolution refers to the changes in allele frequencies within a single population.

There are four fundamental forces of evolution: Natural Selection, Genetic Drift, Mutations and Gene Flow

One of the main controversial issues in population genetics is concerned with the relative importance of both mechanisms in determining evolutionary changes

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it is a better alternative