A Markov chain is a discrete random process with the property that the next state depends only on the current state (wikipedia). A Markov chain is a discrete random process with the property that the next state depends only on the current state (wikipedia). So $P(X_n | X_1, X_2, \ldots X_n-1) = P(X_n | X_{n-1})$.
Some people find molecules and compounds confusing. Here's how to remember the difference. If you join two different chemical elements together, you can often make a completely new substance. Glue two atoms of hydrogen to an atom of oxygen and you'll make a single molecule of water.
They can even be made up of just one atom. The element argon is a one-atom molecule. Other molecules can consist of two atoms of the same element. The oxygen molecule is made up of two oxygen atoms bonded together.However, in certain circumstances, three oxygen atoms bond together, forming a molecule called ozone.IND OUT MORE. Most atoms join up with other atoms through chemical BONDS to form larger particles called molecules. They can join up with atoms of the same element or with atoms of different elements. Substances whose molecules contain different types of atom are called compounds.