Mendel was the first scientist to study the pattern of inheritance. He is known as the father of genetics and proposed the laws of inheritance. He selected pea plants (Pisum sativum) to carry out his study on the inheritance of characters from parents to offspring. Mendel carried the process of self-pollination followed by cross-pollination in his experiment.
________ is a piece of DNA that codes for one protein.

Options

A. Gene
B. Allele
C. Genotype
D. Phenotype

Answer

To solve the question, we need to identify the term that describes a piece of DNA that codes for one protein. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Question
The question asks for a specific term that refers to a segment of DNA responsible for coding a protein.

### Step 2: Analyze the Options
We have four options to consider:
1. Gene
2. Allele
3. Genotype
4. Phenotype

### Step 3: Define Each Term
- **Gene**: A gene is a specific sequence of DNA that contains the information to produce a particular protein. It is the fundamental unit of heredity.
- **Allele**: An allele is a variant form of a gene. While genes can have multiple alleles, an allele itself does not code for a protein.
- **Genotype**: The genotype refers to the genetic makeup of an individual, which includes all the genes they possess, but it does not specifically refer to a segment of DNA coding for a protein.
- **Phenotype**: The phenotype is the observable physical characteristics of an organism, which result from the interaction of the genotype with the environment.

### Step 4: Identify the Correct Answer
From the definitions, it is clear that the term that specifically refers to a piece of DNA that codes for one protein is **Gene**.

### Final Answer
**Gene** is the piece of DNA that codes for one protein.

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