Biology Revision for "O" level examinations

In the video below, the process of Mitosis is explained. 

Skin lightening, or skin bleaching, is a cosmetic procedure that aims to lighten dark areas of skin or achieve a generally paler skin tone. Side effects of skin-lightening creams can include: skin irritation and inflammation (redness and swelling) a burning or stinging sensation itchy and flaky skin uneven colour loss increased risk of cancer Skin whitening creams contain ingredients that act to slow the production of melanin in the skin’s outer layer.

-It is  a medical process for ending pregnancy -Persons choice to undergo abortion is largely influenced by their religious beliefs and cultural beliefs as well as legality of the process in their country Reasons for Abortion -pregnancy may be at a greater risk to the woman’s life than ending the pregnancy -pregancy may cause a greater risk of injury to the woman’s mental or physical health When it should be done -It should occur as early as possible during pregnancy (ideally before 12 th week), when it is easier and safer. If a woman’s life is in danger, then there is no legal time limit for it to occur. -up to 9 weeks in pregnancy (9 weeks since last period) an abortion pill may be used -from 14 weeks onwards, a surgical method is usually required. -Abortion should always be carried out under medical supervision

-Smoking (first or second hand) may result in miscarriage, stillbirth, or premature birth: chemicals in the smoke affect the placenta ( placental abruption: a condition when the placenta separates from the uterus before childbirth ), and causes slow foetal development. -Alcohol affects development of baby's nervous system. -Illicit drugs such as marijuana and cocaine  can cause mental retardation, miscarriage, or physical defects of child - Only drugs prescribed by doctors should be used. Aspirin, Advil, and Motrin can cause fetal heart defects -X-ray: during pregnancy, this can cause genetic mutations in foetus, causing abnormal development. Ultra sound is a safer method, to do internal examination of the body