Fast heart rate: Tachycardia means fast heart beat. Sinus node is the structure where normally heart rhythm and beat is originated, and it naturally responds to stimuli when the heart needs to beat faster. Inappropriate sinus tachycardia is when the heart is beating fast, when it shouldn't. ...Read more.
An atom is the smallest unit of an element that retains the identity (and the chemical properties) of that element. + 66 others found this useful. Sandra Pinzon.Edit.he atom is the smallest particle of an element that retains it's characteristics. Sub-atomic particles such as protons, neutrons and electrons form the atom and it is the amo â¦ unt of each of these sub-atomic particles that make the element that element. 5 people found this useful.
Most of the substances around us consist of molecules and are called compounds of various elements. Molecules are the smallest particle of a compound that has all the chemical properties of that compound. They are made up of two or more atoms, either of the same element or of two or more different elements.olecules and compounds contain their constituent elements in specific proportions that are characteristic of the compound. For example, water (H 2 O), a well known and simple compound, contains hydrogen and oxygen at a ratio of 2 to 1.