They are considered so because are the indispensable parts of the nature cycle.Without formation,decay cannot be possible and similarly,formation cannot be possible without decay.In addition to this,THEY ARE IN A CHRONOLOGICAL MANNER SET BY NATURE and that's why cannot be seperated and so together constitute the cycle of nature.
The mass on mars is 38 percent of earth. Ex: dog weighs 100 on earth, and 38 on mars. 38 percent of 150 is 57 :P
this ones simple all the others don't use sunlight because they cant make food within themselves but plants on the other hand use direct sunlight to make their food unlike the others. ;]
B)Facilitated diffusion is a form of active transport. Regular diffusion is a form of passive transport.
