Question

in roses, red flowers and long stems are dominant traits. a rose plant that is homozygous for both red flowers and long stems is crossed with a rose plant that is heterozygous for red flowers and homozygous for short stems. what percentage of the offspring will exhibit red, long - stemmed flowers? 25 percent 50 percent 75 percent 100 percent

Explanation:

Step1: Determine the genotypes

Let \(R\) represent the allele for red flowers (dominant) and \(r\) for non - red flowers. Let \(L\) represent the allele for long stems (dominant) and \(l\) for short stems.
The homozygous dominant plant has genotype \(RRLL\). The heterozygous red - flowered and homozygous short - stemmed plant has genotype \(Rrll\).

Step2: Use the Punnett square (or probability rules)

For the flower color: \(RR\times Rr\). Using the cross \(RR\times Rr\), the possible genotypes of offspring for flower color are \(RR:Rr = 1:1\). Since \(R\) (red) is dominant, all offspring (\(100\%\)) will have red flowers.
For the stem length: \(LL\times ll\). Using the cross \(LL\times ll\), all offspring will have genotype \(Ll\). Since \(L\) (long) is dominant, all offspring (\(100\%\)) will have long stems.
Since both traits are independent (assuming Mendelian inheritance and no linkage), we use the multiplication rule for independent events. The probability of red flowers (\(P(R) = 1\)) and the probability of long stems (\(P(L)=1\)). The probability of red and long - stemmed flowers \(P(R\cap L)=P(R)\times P(L)\)

Answer:

100 percent