Which of these is a homogeneous mixture? a. a salad b. seawater c. soil d. raisin bread

Is the alien theory a scientific claim? why or why not? just took the test it was , : " the alien theory is not a scientific claim because it is not based on valid data, there is no evidence to support it, and it does not come from a reliable source."

If element x has 99 protons how many electrons does it have

Which system of units is used by only a small number of countries in the world, including the u. s.