Punnett square worksheet illustrating monohybrid crosses for various genetic traits with examples and solutions.

Problem Overview:

The task involves completing monohybrid crosses using Punnett squares. For each cross, we need to:
1. Draw the Punnett square.
2. List the genotypic ratio.
3. Describe the phenotypes of the offspring.

The instructions specify that capital letters represent dominant alleles, and lowercase letters represent recessive alleles.

---

Solution:

#### Example:
A green pea plant (GG) is crossed with a green pea plant (Gg).

- Punnett Square:
```
G G
G GG GG
g Gg Gg
```

- Genotypic Ratio:
- GG : Gg = 2 : 2 (or simplified to 1 : 1)

- Phenotypic Ratio:
- All offspring will be green (since G is dominant over g).

---

#### Problem 1:
A green pea plant (GG) is crossed with a yellow pea plant (gg).

- Punnett Square:
```
G G
g Gg Gg
g Gg Gg
```

- Genotypic Ratio:
- Gg : gg = 4 : 0 (all Gg)

- Phenotypic Ratio:
- All offspring will be green (since G is dominant over g).

---

#### Problem 2:
A tall plant (TT) is crossed with a tall plant (TT).

- Punnett Square:
```
T T
T TT TT
T TT TT
```

- Genotypic Ratio:
- TT : Tt = 4 : 0 (all TT)

- Phenotypic Ratio:
- All offspring will be tall (since T is dominant over t).

---

#### Problem 3:
A tall plant (Tt) is crossed with a short plant (tt).

- Punnett Square:
```
T t
t Tt tt
t Tt tt
```

- Genotypic Ratio:
- Tt : tt = 2 : 2 (or simplified to 1 : 1)

- Phenotypic Ratio:
- Tall : Short = 2 : 2 (or simplified to 1 : 1)
- Explanation: T is dominant over t, so Tt will express the tall phenotype.

---

#### Problem 4:
A red flower (RR) is crossed with a white flower (rr).

- Punnett Square:
```
R R
r Rr Rr
r Rr Rr
```

- Genotypic Ratio:
- Rr : rr = 4 : 0 (all Rr)

- Phenotypic Ratio:
- All offspring will be red (since R is dominant over r).

---

#### Problem 5:
A white flower (rr) is crossed with a white flower (rr).

- Punnett Square:
```
r r
r rr rr
r rr rr
```

- Genotypic Ratio:
- rr : rr = 4 : 0 (all rr)

- Phenotypic Ratio:
- All offspring will be white (since there are no dominant alleles).

---

#### Problem 6:
A black chick (BB) is crossed with a black chick (BB).

- Punnett Square:
```
B B
B BB BB
B BB BB
```

- Genotypic Ratio:
- BB : Bb = 4 : 0 (all BB)

- Phenotypic Ratio:
- All offspring will be black (since B is dominant over b).

---

Final Answer:

\boxed{
\begin{array}{l}
\text{Problem 1:} \\
\text{Genotypic Ratio: } Gg : gg = 4 : 0 \\
\text{Phenotypic Ratio: } \text{All green} \\
\\
\text{Problem 2:} \\
\text{Genotypic Ratio: } TT : Tt = 4 : 0 \\
\text{Phenotypic Ratio: } \text{All tall} \\
\\
\text{Problem 3:} \\
\text{Genotypic Ratio: } Tt : tt = 2 : 2 \\
\text{Phenotypic Ratio: } \text{Tall : Short = 2 : 2} \\
\\
\text{Problem 4:} \\
\text{Genotypic Ratio: } Rr : rr = 4 : 0 \\
\text{Phenotypic Ratio: } \text{All red} \\
\\
\text{Problem 5:} \\
\text{Genotypic Ratio: } rr : rr = 4 : 0 \\
\text{Phenotypic Ratio: } \text{All white} \\
\\
\text{Problem 6:} \\
\text{Genotypic Ratio: } BB : Bb = 4 : 0 \\
\text{Phenotypic Ratio: } \text{All black} \\
\end{array}
}