Ken needs to measure out 50 ml of water. which of the following is the best tool for ken to use?

Graduated Cylinder is probably the best choice.

Engineers have contribute to society in many ways like making the technology we use today or any type of power energy material

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom