Periods | Hormones | Fertility on Instagram: "Once pregnancy begins, the female body activates a powerful biological “security system” to protect the growing baby. The very first change happens in the cervix — the gateway between the vagina and uterus. After fertilization, rising progesterone hormone thickens the cervical mucus into a solid, jelly-like mucus plug. This plug completely seals the cervix, acting as a biological lock that blocks sperm, bacteria, and external particles from entering

Explaining Biology on Instagram: "Biology doesn’t have to be confusing or boring. Sometimes, all it takes is a simple visual to make complex concepts finally click. Biological valves are found throughout the human body—inside veins, the heart, and other systems—working silently to ensure blood and fluids flow in the right direction. These valves open when pressure moves forward and close instantly to prevent backflow, protecting the body from serious complications. This quick demonstration shows

Biology Quiz: Test Your Knowledge