Diagram illustrating how the physical distance between genes on a chromosome affects the strength of their linkage.

Let's solve the problem step by step based on the image you've described.

---

Question 1(a):

Gene A and gene B are said to be linked. Explain what is meant by this.

#### ✔ Answer:
Genes A and B are said to be linked if they are located close together on the same chromosome. Because they are physically close, they tend to be inherited together during meiosis (cell division that produces gametes), rather than assorting independently. This means that unless a crossover event occurs between them, the alleles of these two genes will be passed on as a unit.

> 🔍 Key Concept:
> Linked genes do not follow Mendel’s Law of Independent Assortment because their inheritance is dependent on their physical proximity on a chromosome.

---

Question 1(b):

Explain which chromosome shows the strongest linkage between genes A and B.

We are given three chromosomes:

- Chromosome 1: Gene A and Gene B are at opposite ends of the chromosome.
- Chromosome 2: Gene A and Gene B are located very close to each other in the middle.
- Chromosome 3: Gene A and Gene B are located near each other but not as close as in Chromosome 2.

#### ✔ Answer:
Chromosome 2 shows the strongest linkage between genes A and B.

#### 📌 Explanation:
The strength of linkage depends on the physical distance between the two genes on the chromosome. The closer the genes are, the less likely it is that a crossover (recombination) will occur between them during meiosis. Therefore, they are more likely to be inherited together.

- In Chromosome 2, the genes are very close to each other → low chance of recombination → strong linkage.
- In Chromosome 1, the genes are far apart → high chance of recombination → weak linkage.
- In Chromosome 3, the genes are moderately close → moderate linkage.

Thus, Chromosome 2 has the strongest linkage due to the shortest distance between genes A and B.

---

✔ Final Answers:

(a) Genes A and B are said to be linked when they are located close together on the same chromosome and tend to be inherited together during meiosis.

(b) Chromosome 2 shows the strongest linkage because genes A and B are closest together, making recombination between them less likely.

---

Let me know if you'd like a diagram explanation or further details!