مالیکیولز (Molecules) are the smallest units of a chemical compound that retain its properties. They are made up of two or more atoms that are bonded together. These atoms can be of the same element, like in O2 (oxygen gas), or different elements, such as in H2O (water). Molecules play a crucial role in chemistry and biology, as they form the basis of all matter. They can vary in size and complexity, from simple molecules like CO2 (carbon dioxide) to large biological molecules like DNA. Understanding molecules helps scientists study reactions and the behavior of substances.