What is the control, group, experimental group, independent variable, dependent variable

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.

Which organisms have pharyngeal arches that develop from all three germ layers and go through the same development stages as embryos? 1.bird 2.ladybug 3.starfish 4.snake

The bacteria found in soil is usually harmful and measures are taken to remove any traces of microorganisms. true or false