State:Two contributions of T.H. Morgan.

Answer

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

1. **Identify T.H. Morgan**: T.H. Morgan, or Thomas Hunt Morgan, was an influential scientist known for his work in genetics. He lived from 1866 to 1945 and was awarded the Nobel Prize in Physiology or Medicine in 1933.

2. **Contribution 1 - Chromosomal Theory of Linkage**: One of Morgan's significant contributions was his research on the fruit fly, Drosophila melanogaster. Through his experiments, he proposed the chromosomal theory of linkage, which explains how genes that are located close to each other on the same chromosome tend to be inherited together.

3. **Contribution 2 - Genes on Chromosomes**: Morgan also established that genes are located on chromosomes. This was a pivotal discovery in genetics, as it helped to clarify the relationship between chromosomes and heredity, laying the groundwork for modern genetics.

**Final Answer**:
1. Proposed the chromosomal theory of linkage.
2. Established that genes are located on chromosomes.

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