The law of segregation is universally applicable.

Explanation

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

1. **Understanding the Law of Segregation**: The law of segregation, proposed by Gregor Mendel, states that during the formation of gametes (sperm and egg cells), the two alleles for a trait separate from each other so that each gamete carries only one allele for each gene.

2. **Alleles and Traits**: In the context of a trait such as plant height, there are two contrasting forms of a gene known as alleles. For example, one allele may code for tallness (dominant) and the other for shortness (recessive).

3. **Presence of Alleles**: In a diploid organism, such as a plant or animal, both alleles are present in the organism's cells. However, they do not blend together; instead, they remain distinct.

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