Final answer:
The basic units containing immature egg cells in the female reproductive system are follicles, which are located within the ovaries and release the egg during ovulation.
Step-by-step explanation:
The basic units of the female reproductive system that each contain a single immature egg cell released during ovulation are known as follicles. The ovaries, which are part of the internal female reproductive structures, house these follicles. During each menstrual period, a batch of follicular cells, which function as the protective and nourishing environment for the egg, develops and gets prepared for the process of ovulation. When ovulation occurs, the ripe follicle ruptures to release the egg cell. This process is critical for reproduction as it makes the egg available for potential fertilization. After the release of the egg, the follicle transforms into the corpus luteum, which secretes hormones essential for pregnancy maintenance.
The basic units of the female reproductive system that contain a single immature egg cell are called ovarian follicles. Each follicle consists of one or more follicular cells that surround, nourish, and protect a single egg. During ovulation, one follicle ruptures and releases an egg.