The onset of puberty in females triggers the shedding of unfertilised eggs and the LINING OF THE UTERUS. The lining of the uterus is shed each month if the mature egg is not fertilized. This process is called menstruation. The first menstrual period a young girl will have marks menarche.
Specialized hormones such as progesterone and estrogens play a vital role in the development and shedding of the lining of the uterus in each menstrual cycles.
Carcinogens is a substance capable of causing cancer in living tissue.
Answer is: cancer causing agents
The first time a pathogen hits, our bodies do not know how to handle it properly. This means that our bodies take more time to handle it the first time around. The second time around, however, our bodies have altered so that they can handle the pathogen more efficiently. Hope this helps!
You should really include the article with the question. Makes it easier for those wanting to answer
