What does a Punnett Square help to predict?

• A. The weather patterns
• B. The outcome of simple genetic crosses
• C. The cost of genetic testing
• D. The lifespan of different organisms

Answer: (B)

A Punnett Square is a tool used in genetics to visualize the possible combinations of alleles that offspring may inherit from their parents during a genetic cross. It organizes the parental genotypes and allows for the calculation of the probabilities of different genotypes in the offspring. By filling in the square with the allele combinations from each parent, it becomes clear how traits may be passed on and what the potential ratios of traits in the next generation will be.

This method is particularly useful for simple genetic crosses, typically involving single gene traits that follow Mendelian inheritance patterns, such as dominant and recessive alleles. For instance, if studying a cross between two pea plants where one is homozygous dominant for a trait and the other is homozygous recessive, the Punnett Square will clearly show that all offspring will express the dominant trait.

In contrast, the other choices do not relate to the function of a Punnett Square. Weather patterns, costs of genetic testing, and lifespans of organisms involve factors that do not pertain to genetic inheritance and cannot be represented or predicted through a Punnett Square. Therefore, the use of this tool is specifically beneficial in understanding the outcomes of simple genetic crosses.