Answer :
To solve this problem, we need to understand the genetics behind the traits for flower color in geraniums and how to use a Punnett square to predict the outcome of a genetic cross.
### Genetic Traits:
- Red flowers trait: Governed by the dominant allele [tex]\( R \)[/tex]. A geranium with red flowers can be either homozygous dominant ([tex]\( RR \)[/tex]) or heterozygous ([tex]\( Rr \)[/tex]).
- White flowers trait: Governed by the recessive allele [tex]\( r \)[/tex]. A geranium with white flowers must be homozygous recessive ([tex]\( rr \)[/tex]).
### The Cross:
The horticulturalist plans to cross a true-breeding red-flowered geranium with a true-breeding white-flowered geranium.
- A true-breeding red-flowered geranium has the genotype [tex]\( RR \)[/tex].
- A true-breeding white-flowered geranium has the genotype [tex]\( rr \)[/tex].
### Punnett Square:
To determine the possible genotypes of the offspring, we set up a Punnett square using these genotypes.
1. Parent Genotypes:
- Parent 1 (Red): [tex]\( RR \)[/tex]
- Parent 2 (White): [tex]\( rr \)[/tex]
2. Create the Punnett Square:
- Place one parent's alleles on the top and the other parent's alleles along the side.
- In this case, every offspring receives one [tex]\( R \)[/tex] allele from the red-flowered parent and one [tex]\( r \)[/tex] allele from the white-flowered parent.
3. Offspring Genotypes:
- Each box in the Punnett square represents a possible genotype for the offspring.
- For our cross between [tex]\( RR \)[/tex] and [tex]\( rr \)[/tex], each combination results in [tex]\( Rr \)[/tex].
4. Resulting Punnett Square:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline & r & r \\
\hline R & Rr & Rr \\
\hline R & Rr & Rr \\
\hline
\end{tabular}
\][/tex]
All offspring will be heterozygous [tex]\( Rr \)[/tex], meaning they will all have red flowers due to the dominant [tex]\( R \)[/tex] allele.
### Conclusion:
The Punnett square that correctly represents this genetic cross shows that all offspring will be [tex]\( Rr \)[/tex], with red flowers. Therefore, the correct Punnett square is option C.
### Genetic Traits:
- Red flowers trait: Governed by the dominant allele [tex]\( R \)[/tex]. A geranium with red flowers can be either homozygous dominant ([tex]\( RR \)[/tex]) or heterozygous ([tex]\( Rr \)[/tex]).
- White flowers trait: Governed by the recessive allele [tex]\( r \)[/tex]. A geranium with white flowers must be homozygous recessive ([tex]\( rr \)[/tex]).
### The Cross:
The horticulturalist plans to cross a true-breeding red-flowered geranium with a true-breeding white-flowered geranium.
- A true-breeding red-flowered geranium has the genotype [tex]\( RR \)[/tex].
- A true-breeding white-flowered geranium has the genotype [tex]\( rr \)[/tex].
### Punnett Square:
To determine the possible genotypes of the offspring, we set up a Punnett square using these genotypes.
1. Parent Genotypes:
- Parent 1 (Red): [tex]\( RR \)[/tex]
- Parent 2 (White): [tex]\( rr \)[/tex]
2. Create the Punnett Square:
- Place one parent's alleles on the top and the other parent's alleles along the side.
- In this case, every offspring receives one [tex]\( R \)[/tex] allele from the red-flowered parent and one [tex]\( r \)[/tex] allele from the white-flowered parent.
3. Offspring Genotypes:
- Each box in the Punnett square represents a possible genotype for the offspring.
- For our cross between [tex]\( RR \)[/tex] and [tex]\( rr \)[/tex], each combination results in [tex]\( Rr \)[/tex].
4. Resulting Punnett Square:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline & r & r \\
\hline R & Rr & Rr \\
\hline R & Rr & Rr \\
\hline
\end{tabular}
\][/tex]
All offspring will be heterozygous [tex]\( Rr \)[/tex], meaning they will all have red flowers due to the dominant [tex]\( R \)[/tex] allele.
### Conclusion:
The Punnett square that correctly represents this genetic cross shows that all offspring will be [tex]\( Rr \)[/tex], with red flowers. Therefore, the correct Punnett square is option C.
