_____ provides nutrition for the egg in the embryo sac.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Embryo Sac**: The embryo sac is a structure found within the ovule of flowering plants. It contains the egg cell and is crucial for reproduction in plants.

2. **Identifying the Role of the Nucleus**: In the context of the embryo sac, the nucleus refers to the central part of the ovule where the egg cell is located. It is essential for the development of the embryo.

3. **Nutritional Function**: The nucleus provides nutrition to the egg cell within the embryo sac. It serves as a source of food that supports the growth and development of the embryo after fertilization.

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