How can a protein outside the cell cause events to happen inside the cell?

Explained

Explanation:

The proteins(sometimes are called celluar ligands) outside the cell can bind to a receptor protein( generally found on the cell membranes) on the cell surface, causing it( receptor protein) to change the shape and sending a signal inside the cell.

change tension

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.