The primary biological importance of sex in organisms is that it

Options

A. Is essential for organismic reproduction
B. Is essential for cellular reproduction
C. Causes new mutations to occur in offspring
D. Promotes genetic variability in offspring

Explanation

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

1. **Understanding Sexual Reproduction**: Sexual reproduction involves the fusion of genetic material from two parents, typically a male and a female. This process is known as bi-parental reproduction.

2. **Genetic Contribution**: In sexual reproduction, offspring inherit genes from both parents. This means that the genetic makeup of the offspring is a combination of the traits from both the mother and the father.

3. **Importance of Genetic Variability**: The mixing of genetic material from two different individuals leads to genetic variability in the offspring. This variability is crucial for the adaptation and evolution of species.

4. **Mechanisms of Variation**: Genetic variability can arise from several mechanisms, including crossing over during meiosis, independent assortment of chromosomes, and random fertilization. These processes create new combinations of genes, leading to diverse traits in the offspring.

5. **Evolution and Survival**: The genetic diversity resulting from sexual reproduction is essential for the survival of species. It allows populations to adapt to changing environments and resist diseases, thereby promoting the overall fitness of the species.

6. **Conclusion**: The primary biological importance of sex in organisms is that it promotes genetic variability in offspring, which is vital for evolution and the survival of species.

**Final Answer**: The primary biological importance of sex in organisms is that it promotes genetic variability in offspring.

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