Â­Mesoamericans began writing during the mid-Pre-classic period. The Mayans were the first to keep any sort of historical record, and the beginnings of the calendar were born. The Mayans used stelae, or stone monuments, to carve their civil events, calendars and astronomy knowledge. They also inscribed their religious beliefs and mythology on pottery.
The nucleus is a membrane bound structure that contains the cell's hereditary information and controls the cell's growth and reproduction. It is commonly the most prominent organelle in the cell. The nucleus is surrounded by a structure called the nuclear envelope.
The nucleus is one of the most important organelles in a cell. It is often the largest organelle in animal cells, but this is not always the case. Nuclei contain the genetic material called DNA that is responsible for controlling and directing all cell activities.he Cytoplasm is the gel-like substance that fills the cell outside the nucleus. All of the cell's organelles are held and located within the cytoplasm. There are many different chemicals, nucleic acids, and other substances that the cell needs can be found there also. It supports the cell and gives it shape.