Why do scientist typically run multiple trials for the experimental group

Kelly ran electricity though a sample of water using electrolysis. the water changed into two gases, x and y. it was not possible to break down the gases x and y into simpler particles.

This is one of the five kingdoms in the older biological succession. organisms in this kingdom are prokaryotic.

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems