Northam Warren created the first commercial version of LIQUID NAIL POLISH in 1917.
As the name implies, the LIQUID NAIL POLISH is used on finger nails, to make it look more attractive and beautiful.
This was after he created the fingernail cuticle remover and nail polish in 1911, and nail tints in 1914.
Answer:A): four electron shells
Explanation:
In the period table, atoms are arranged in rows called periods and columns called groups. The arrangement of atoms in groups is based on the number of their valence electrons while the arrangement of atoms across the periods is based on their number of electrons shells. Atoms are arranged across the periods in increasing order of their atomic number i.e., according to their number of electrons. Potassium has 19 electrons while copper has 29 electrons. Both has four electrons shells according to their electronic configuration.
The loop prevention technique implemented by distance vector routing protocol is SPLIT HORIZON.
Routing loop is a common problem that is associated with networks. Routing loop is said to occur when an error arise in the operation of the routing algorithm which leads to formation of nodes and loops in the path to a particular destination. Split horizon is one of the feature that is used to prevent distance vector routing.<span />