Sedimentary<span> rocks are formed when </span>sediment<span> is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. This </span>sediment<span> is often formed when weathering and erosion break down a rock into loose material in a source area.</span>
These cells consume bacteria and other pathogens to protect the body from infection. The process begins when chemicals from a pathogen, or damaged tissue, attract a phagocyte. The phagocyte binds to the microbe, envelopes it, and then eats it.
The yolk sac functions to form blood cells in early development (embryonic phase) for nourishment of the embryo and early fetus. Towards the end of the 1st trimester, the yolk sac disappears and the placenta takes over for the fetus.
