Which of these is a pure substance that cannot be broken down by a chemical reaction?
O a neutron
O a compound
O an element
O a mixture

an element

Explanation:

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.

on the planet jupiter, the acceleration due to gravity is approximately 26 m s2 , roughly 2.7 times the acceleration due