Answer :
Certainly! Let's work through the cross of the geraniums using a Punnett square.
### Problem Understanding:
1. Traits and Alleles:
- Red flowers are governed by the allele [tex]\( R \)[/tex]. Red flowers occur when the genotype is either [tex]\( RR \)[/tex] or [tex]\( Rr \)[/tex].
- White flowers are governed by the allele [tex]\( r \)[/tex]. White flowers occur only when the genotype is [tex]\( rr \)[/tex].
2. Cross Information:
- A geranium that is true-breeding for red flowers will have the genotype [tex]\( RR \)[/tex].
- A geranium that is true-breeding for white flowers will have the genotype [tex]\( rr \)[/tex].
### Setting Up the Punnett Square:
- Parent Genotypes:
- One parent is [tex]\( RR \)[/tex] (red flowers).
- The other parent is [tex]\( rr \)[/tex] (white flowers).
To find out the possible genotypes of the offspring when these two plants are crossed, we can use a Punnett square.
### Completing the Punnett Square:
1. Labeling the square:
- On the top of the square, place the alleles from one parent.
- On the side of the square, place the alleles from the other parent.
Since one parent is [tex]\( RR \)[/tex] and the other is [tex]\( rr \)[/tex], it will look like this:
[tex]\[
\begin{array}{c|c|c}
& R & R \\
\hline
r & & \\
\hline
r & & \\
\end{array}
\][/tex]
2. Filling in the possible offspring genotypes:
- The first intersection (top left): [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results in [tex]\( Rr \)[/tex].
- The top right: [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results in another [tex]\( Rr \)[/tex].
- The bottom left: [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results again in [tex]\( Rr \)[/tex].
- The bottom right: [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results in [tex]\( Rr \)[/tex].
The completed Punnett square looks like this:
[tex]\[
\begin{array}{c|c|c}
& R & R \\
\hline
r & Rr & Rr \\
\hline
r & Rr & Rr \\
\end{array}
\][/tex]
### Conclusion
- Offspring Genotypes:
- All of the offspring will be [tex]\( Rr \)[/tex], which means they all will have red flowers, as the presence of a single [tex]\( R \)[/tex] allele is enough for the flowers to be red.
Therefore, the correct Punnett square that describes this genetic cross is option C.
### Problem Understanding:
1. Traits and Alleles:
- Red flowers are governed by the allele [tex]\( R \)[/tex]. Red flowers occur when the genotype is either [tex]\( RR \)[/tex] or [tex]\( Rr \)[/tex].
- White flowers are governed by the allele [tex]\( r \)[/tex]. White flowers occur only when the genotype is [tex]\( rr \)[/tex].
2. Cross Information:
- A geranium that is true-breeding for red flowers will have the genotype [tex]\( RR \)[/tex].
- A geranium that is true-breeding for white flowers will have the genotype [tex]\( rr \)[/tex].
### Setting Up the Punnett Square:
- Parent Genotypes:
- One parent is [tex]\( RR \)[/tex] (red flowers).
- The other parent is [tex]\( rr \)[/tex] (white flowers).
To find out the possible genotypes of the offspring when these two plants are crossed, we can use a Punnett square.
### Completing the Punnett Square:
1. Labeling the square:
- On the top of the square, place the alleles from one parent.
- On the side of the square, place the alleles from the other parent.
Since one parent is [tex]\( RR \)[/tex] and the other is [tex]\( rr \)[/tex], it will look like this:
[tex]\[
\begin{array}{c|c|c}
& R & R \\
\hline
r & & \\
\hline
r & & \\
\end{array}
\][/tex]
2. Filling in the possible offspring genotypes:
- The first intersection (top left): [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results in [tex]\( Rr \)[/tex].
- The top right: [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results in another [tex]\( Rr \)[/tex].
- The bottom left: [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results again in [tex]\( Rr \)[/tex].
- The bottom right: [tex]\( R \)[/tex] from the top mating with [tex]\( r \)[/tex] from the side results in [tex]\( Rr \)[/tex].
The completed Punnett square looks like this:
[tex]\[
\begin{array}{c|c|c}
& R & R \\
\hline
r & Rr & Rr \\
\hline
r & Rr & Rr \\
\end{array}
\][/tex]
### Conclusion
- Offspring Genotypes:
- All of the offspring will be [tex]\( Rr \)[/tex], which means they all will have red flowers, as the presence of a single [tex]\( R \)[/tex] allele is enough for the flowers to be red.
Therefore, the correct Punnett square that describes this genetic cross is option C.
