The body’s reproductive system releases hormones and gametes that are needed to produce an offspring.

In males, their reproductive system produces sperm and delivers it to the female’s reproductive system.

In females, their reproductive system produces ova. It also provides nourishment to the developing offspring.

In the menstrual cycle, the egg in the woman’s body develops and is released from the ovary for fertilization. If the egg is fertilized, it will be developed into a zygote, but if it is not fertilized, it will be discharged outside the body. There are four phases in this cycle: the follicular phase, ovulation phase, luteal phase, and menstruation.

Four phases of the menstrual cycle:

1. **Follicular phase** – The hypothalamus creates a response and stimulates the anterior pituitary gland to release FSH and LH in the blood in order for the follicles to develop to maturity.

2. **Ovulation phase** – This is the shortest among the phases, as it only lasts for three to four days. In this phase, the matured egg is released into one of the Fallopian tubes, ready for fertilization.

3. **Luteal phase** – This is the phase after the egg is released into the Fallopian tubes and it will turn into a yellow-colored structure known as *corpus luteum*. The corpus luteum will continue to secrete estrogen, and progesterone helps in the stimulation of cell growth in the uterus lining.

5. **Menstruation** – This is the phase after the egg was **not fertilized**. In this phase, the lining of the uterus will shred and detach along with the blood and unfertilized egg, and it will be discharged outside through the vagina. Menstruation lasts for an average of 3-5 days, and a new cycle will begin after this phase.

**Puberty** is the period or stage of rapid growth and maturation of the sex characteristics of an individual. This is the period in which the reproduction system is fully developed and functional.

**Sexually transmitted disease (STD)** is a type of disease that can spread or transfer from one person to another via sexual contact. It is a severe health problem causing thousands of deaths worldwide. There are different kinds of STDs but the most common are **Chlamydia** and **AIDS**

**Chlamydia** – is bacterial infection caused by a bacteria named ***Chlamydia trachomatis***. It is considered a sexually transmitted disease because the infection can be passed from one person to another via sexual contact including those acts that do not involve ejaculation. This is because the main media for the bacterial species is the vaginal fluid or the semen. In the United States, more than 3 million cases of chlamydia happen every year, affecting ages 15 and 19 the most.

**Acquired Immunodeficiency Syndrome (AIDS)** – is an infection caused by a virus known as **human immunodeficiency virus (HIV)**. It is an infection that severely damages the immune system causing many complications in other organs. This infection cannot be treated or cured by any antibiotics, and it causes millions of deaths globally.

**Ovulation phase** is the shortest among the menstrual phases, as it only lasts for three to four days. In this phase, the matured egg is released into one of the Fallopian tubes, ready for fertilization.

During this phase, the hypothalamus releases and secretes signals to the pituitary gland to initiate the production of Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH). LH reached its peak at the time when the egg is released from the ovary. Hence, it is the correct answer.

Luteinizing hormone