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.
Report Abuse. All eukaryotic cells (which means  has true nucleus) have a nucleus. However, certain cells called Prokaryotic cells (meaning no true nucleus) do not have a nucleus. Instead, their genetic data simply floats around the inside of the cell like water outside of a glass.All plants and animals have very complex Eukaryotic cells.The main difference between plant cells and animal cells, rather than nucleus or no nucleus, is that plants have an extra protective layer around the cell called a cell wall.ll plants and animals have very complex Eukaryotic cells. The main difference between plant cells and animal cells, rather than nucleus or no nucleus, is that plants have an extra protective layer around the cell called a cell wall.