The answer is A Recognition of value
Scientists will look for evidence like similar body or skeleton structures, internal similarities or maybe sometimes the whole heirarchy to confirm that two speices are closely related to each other.
For example ; in birds, scientists will look for type of feathers, body structure, beaks to confirm the similarity of two birds.
Humans and chimps genes may have split 13 million years ago.
Photosynthesis is one of the main processes that is basically responsible for the function of all living things. Without it carbon would not be cycled, oxygen would not be made and plants would not be able to creat food for themselves and would have to rely on another source.