Miller, F.Skoog and hig co-workers are concered to discovery of

Answer

**Step-by-Step Text Solution:**

1. **Identify the Researchers**: The question mentions Miller, F. Skoog, and their co-workers. It's important to recognize who they are in the context of plant biology.

2. **Understand Their Contribution**: These researchers are known for their work in plant growth regulators, specifically focusing on the discovery of a particular type of hormone.

3. **Name the Discovery**: They discovered a plant growth regulator known as cytokinin. This was a significant finding in the field of plant physiology.

4. **Context of the Discovery**: The discovery of cytokinins occurred in the 1950s. This was a pivotal time for understanding how plant hormones affect growth and development.

5. **Cytokinin Hypothesis**: Along with the discovery, they proposed the "Auxin and Cytokinin Hypothesis," which explains the relationship between these hormones in promoting root and shoot formation in plants.

6. **Conclusion**: Therefore, Miller, F. Skoog, and their co-workers are primarily concerned with the discovery of cytokinins and their role in plant growth.

**Final Answer**: Miller, F. Skoog, and their co-workers are concerned with the discovery of cytokinin, a plant growth regulator.

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