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.
Parts of the animal cell are as follows: Cell membrane-forms the outer covering of the cell, and is semi-permeable. Cytoplasm-is a gel-like matrix where all the other cell organelles are suspended inside the cell. Nucleus-contains the hereditary material DNA and directs the activities of the cell.arts of the animal cell are as follows: Cell membrane-forms the outer covering of the cell, and is semi-permeable. Cytoplasm-is a gel-like matrix where all the other cell organelles are suspended inside the cell. Nucleus-contains the hereditary material DNA and directs the activities of the cell.