What number system that has 16 numerals

hexadecimal

The hexadecimal numeral system, often shortened to "hex", is a numeral system made up of 16 symbols (base 16). The standard numeral system is called decimal (base 10) and uses ten symbols: 0,1,2,3,4,5,6,7,8,9. Hexadecimal uses the decimal numbers and six extra symbols

Hexadecimal

Explanation:

The hexadecimal numeral system, often shortened to "hex", is a numeral system made up of 16 symbols (base 16). The standard numeral system is called decimal (base 10) and uses ten symbols: 0,1,2,3,4,5,6,7,8,9. Hexadecimal uses the decimal numbers and six extra symbols.

these  signals travel  down a part of the neuron called the axon, which is like a wire that carries the  signal  to othernerve  cells. on average a  nerve  cell sends a  signal  at about 50 meters per second, which is over 100  miles  an hour!