Characters are controlled by discrete units called :-

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the units that control characters in genetics.

2. **Identifying the Key Concept**: In genetics, characters (traits) are controlled by discrete units. These units are fundamental to the study of inheritance.

3. **Introducing the Term**: The term that describes these discrete units is "factors." Historically, these were referred to as factors.

4. **Modern Terminology**: In contemporary genetics, these factors are now more commonly known as "alleles."

5. **Law of Dominance**: According to Gregor Mendel's Law of Dominance, when two alleles are present, one may dominate the other. This means that in a hybrid organism (an organism with two different alleles for a trait), only one allele will express itself while the other remains hidden.

6. **Defining Alleles**: Alleles are variations of a gene that can produce different traits. For example, a gene for flower color may have a red allele and a white allele.

7. **Conclusion**: Therefore, the correct answer to the question is that characters are controlled by discrete units called "alleles."

**Final Answer**: Characters are controlled by discrete units called alleles.

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