Sex of the offspring depends on the fertilizing ovum in

Options

A. Fruit fly, Butter fly
B. Grass hoppers, cockroaches
C. Fumea, birds
D. Squash bug, Drosophila

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the dependence of the sex of the offspring on the fertilizing ovum. This indicates that we need to explore the concept of sex determination in different organisms, focusing on whether the female gamete (ovum) plays a role in determining the sex.

2. **Defining Male and Female Heterogametes**:
- Male heterogametes: In organisms like humans, males have two types of sex chromosomes (X and Y). The female gamete (ovum) can only carry X chromosomes, while the male gamete (sperm) can carry either X or Y. The combination of these determines the sex of the offspring.
- Female heterogametes: In some organisms, females have two types of sex chromosomes (e.g., Z and W). In this case, the ovum can carry either Z or W, while the male gamete (sperm) carries only Z. The combination of these also determines the sex of the offspring.

3. **Examples of Organisms**:
- In humans and grasshoppers, the male is the heterogametic sex (XY), meaning the male determines the sex of the offspring.
- In birds and some butterflies, the female is the heterogametic sex (ZW), meaning the female determines the sex of the offspring.

4. **Analyzing the Options**:
- Option 1: Fruit fly and butterfly - Incorrect, as fruit flies exhibit male heterogamety.
- Option 2: Grasshopper - Incorrect, as grasshoppers also exhibit male heterogamety.
- Option 3: Birds and moths - Correct, as they exhibit female heterogamety.
- Option 4: Squash bug and rose phyllo - Incorrect, as these do not exhibit female heterogamety.

5. **Conclusion**: The correct answer is option number three, which includes birds and moths, as they exhibit female heterogamety where the sex of the offspring is determined by the ovum.