The menstrual cycle, which is counted from the first day of one period to the first day of the next, isn't the same for every woman. Menstrual flow might occur every 21 to 35 days and last two to seven days. For the first few years after menstruation begins, long cycles are common.
Definition: DNA (deoxyribonucleic acid) is a type of macromolecule known as a nucleic acid. It is shaped like a twisted double helix and is composed of long strands of alternating sugars and phosphate groups, along with nitrogenous bases (adenine, thymine, guanine and cytosine).
DNA is the code that directs a cell's actions. In eukaryotes (cells with nuclei, like you have), the DNA is stored in the nucleus. When a gene (a segment of DNA coding for a s â¦ pecific trait) is expressed, a protein is made to fulfill some cell function.