Study the following statements
1. A homozygous tall plant (TT) is crossed with homozygous dwarf (tt), the tall progeny = 100%
2. A heterozygous tall selfed, tall: dwarf = 75% : 25%
3. A heterozygous tall crossed with homozygous dwarf, the tall : dwarf 1 : 1.
4. A heterozygous tall crossed with homozygous dwarf: tall : dwarf = 100 : 0.
a) 1 and 2 are correct
b) 2 and 3 are correct
c) 1, 2 and 3 correct
d) All are correct

Options

A. 1 and 2 are correct
B. 2 and 3 are correct
C. 1, 2 and 3 correct
D. All are correct

Answer

To solve the question, we need to analyze each statement regarding the inheritance of traits in plants, specifically focusing on the tall (T) and dwarf (t) traits. Let's break it down step by step:

### Step 1: Analyze Statement 1
**Statement:** A homozygous tall plant (TT) is crossed with a homozygous dwarf (tt), the tall progeny = 100%.

**Analysis:**
- When a homozygous tall plant (TT) is crossed with a homozygous dwarf plant (tt), all offspring will inherit one T allele from the tall parent and one t allele from the dwarf parent.
- The genotype of all progeny will be Tt (heterozygous tall).
- Since T is dominant over t, all progeny will exhibit the tall phenotype.

**Conclusion:** This statement is correct.

### Step 2: Analyze Statement 2
**Statement:** A heterozygous tall selfed, tall: dwarf = 75%: 25%.

**Analysis:**
- When a heterozygous tall plant (Tt) is self-fertilized, we can set up a Punnett square:
- Gametes: T and t from one parent, T and t from the other parent.
- The resulting genotypes will be: TT, Tt, Tt, and tt.
- The phenotypic ratio will be:
- Tall (TT and Tt) = 3 (75%)
- Dwarf (tt) = 1 (25%)

**Conclusion:** This statement is correct.

### Step 3: Analyze Statement 3
**Statement:** A heterozygous tall crossed with homozygous dwarf, the tall: dwarf = 1:1.

**Analysis:**
- When a heterozygous tall plant (Tt) is crossed with a homozygous dwarf plant (tt), the possible offspring will be:
- Tt (tall) and tt (dwarf).
- The ratio of tall to dwarf will be:
- Tall (Tt) = 1
- Dwarf (tt) = 1

**Conclusion:** This statement is correct.

### Step 4: Analyze Statement 4
**Statement:** A heterozygous tall crossed with homozygous dwarf: tall: dwarf = 100: 0.

**Analysis:**
- As analyzed in the previous step, crossing a heterozygous tall plant (Tt) with a homozygous dwarf plant (tt) results in a 1:1 ratio of tall to dwarf.
- Therefore, the ratio cannot be 100:0.

**Conclusion:** This statement is incorrect.

### Final Conclusion
Based on the analysis:
- Statements 1, 2, and 3 are correct.
- Statement 4 is incorrect.

Thus, the correct answer is **c) 1, 2 and 3 are correct**.

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