The DNA molecule is formed by chains of nuclei that are held together by hydrogen bonds between complementary pairs of nitrogenous bases . Chemically these chains run in opposite directions and form a kind of twisted staircase, a double helix mode, in whose steps are the nitrogenous bases
<span>Earth consists of four major layers: the crust, mantle, outer core and inner core. While most of the layers are made of solid material, there are several pieces of evidence suggesting that the outer core is indeed liquid. Density, seismic-wave data and Earth’s magnetic field provide insight into not only the structure but also the composition of Earth’s core</span>
Some of the causes which might lead to fetus death at four months of gestation include;
1. Poorly controlled maternal conditions, for example, hypertension or diabetes.
2.Eclampsia of pregnancy
3. Trauma.
4. Lupus
5. Physical problem with the uterus.
6. Uterine infection.
7.Fetal abnormalities
8. use of illicit drugs, for example, cocaine.