The answer is C I got it right so hope it helped ;)
Same things but with different numbers of neutrons in nuclei
Distance and time is needed for determining speed
<span>The righ answer is the option A. They are made up of two or more pure substances that are not chemically bonded. A classicall expample ot heterogeneous mixtures are sugar and salt. Sugar is a pure substance, salt is also a pure substance, when you mixe them you form mixture where salt is still salt and sugar is still sugar, that is what "they are not chemically bonded" means. So you can separate them by physical media. </span>