Period number used in a sentence

Numbers use periods in English to separate the whole number from the decimal. A period used in a number is also called a "decimal point" and it is read "point" unless it refers to money

Explanation:

The period number of an element is related to the number of electrons that are in its shell.

zfoods? ok, pressure is used to keep the heat inside and to keep the food perfect.

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.