C, because a half-life is the amount of time it takes for half the atoms to decay.
The answer is a i hope i helped plz i need the brainlyest
The answer is 3). This is because elements are the simplest form of a substance, and cannot be broken down any further. Compounds on the other hand are much more complex than elements and can be broken down INTO elements.
For example, Na, sodium, is an element and cannot be broken down further. H2O, water, is a compound and can be broken down into Hydrogen and Oxygen.
1st qn - B
2nd qn - A
Last qn - Yes
