Germplasm theory against Lamarck’s principle was put forward by

The correct option is Weismann.

Detailed Explanation:

Lamarck’s theory of inheritance of acquired characters (Lamarckism) proposed that changes or traits acquired by an organism during its lifetime due to use or disuse of organs, or environmental influence, could be passed down to its offspring.

To test and challenge this hypothesis, the German biologist August Weismann performed a famous experiment where he cut off the tails of mice for 22 consecutive generations. He observed that the offspring in the 23rd generation were still born with complete tails of normal length. This demonstrated that the acquired trait of taillessness was not inherited.

Based on his findings, Weismann proposed the Germplasm Theory (or Germ Plasm Theory) in 1892. This theory draws a clear distinction between two types of tissues in multicellular organisms:
1. Somatoplasm (Somatic cells): The cells making up the body of an organism. Changes or modifications occurring in somatic cells are not passed to the next generation.
2. Germplasm (Germ cells): The cells responsible for reproduction (gametes like sperm and egg). Only changes that occur in the germplasm can be transmitted to offspring.

Since the mutilation of the mice's tails affected only their somatic cells (somatoplasm) and did not alter their reproductive cells (germplasm), the trait was not inherited. This theory provided a strong scientific argument against Lamarck's principle of the inheritance of acquired characters.