All of the following are possible sources of error in a scientific investigation except for: a- not being able to complete all trials of an experiment b- measuring materials such as mass and volume incorrectly c- having a constant in your experiment d- recording experimental data incorrectly

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.

the answer is c most of the fortnite players usually buy v bucks to get the battle pass and other cosmetics but some players who are referred to as "no skins" don't   buy skins and are usually noobs.