What is a controlled experiment? none of the variables are changed all variables are kept constant two variables are changed at a time one variable is changed at a time

How do you tell if someone actually cares about you? and just say they do?

Carbon 14 is a naturally occurring stable

Aprotein molecule in an electrophoresis gel has a negative charge. the exact charge depends on the ph of the solution, but 30 excess electrons is typical. what is the magnitude of the electric force on a protein with this charge in a 1600n/c electric field? write in two significant numbers, and also in newton