Which two element families are shown at the bottom of the periodic table, separate from the rest of the elements?

According to newton’s first law of motion, which force is expected to cause a body to accelerate?

Which of the following is not a transverse wave? a) soundb) lightc) radiod) all of thesee) none of these

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?