Ima say this in the most easy simplest way possible. Genotype is like the physical make up of an organism. In other terms genotype is the actual genes, the actual alleles. Like PP Pp and pp ( dominant / recessive)
And the phenotype is the physical appearance like the stuff you can actually distinguish a person like curly hair, straight hair, brown eyes, blue eyes, black hair. blond hair. Anyways you get the point.
This is the easiest, simplest way I could put it so I hope it helps.
It's needed for photosynthesis and inturn it gives us oxygen good product for alloys good product for displacement reactions harms global warming global dimming carbon dioxide with a lack of oxygen is poisonous
