What are the events that take place in the ovary and uterus during follicular phase of the menstrual cycle.

Explanation

### Step-by-Step Solution:

1. **Primary Follicle Development**:
- During the follicular phase of the menstrual cycle, the primary follicle in the ovary begins to grow and undergoes maturation. This process leads to the formation of a fully mature Graafian follicle.

2. **Secretion of Estrogen**:
- As the primary follicle develops into a Graafian follicle, it starts secreting estrogen hormones. Estrogen plays a crucial role in regulating various functions in the reproductive system, including the preparation of the uterus for potential implantation.

...