ITS D I THINK PRETTY SURE BUT DO TAKE MY WORD FOR IT.
Answer:I believe it is Carbon
Explanation:The basic building block of all living things is a cell. The basic element would be carbon.
I believe it is D. the genetic variations are in the phenotype of the organism. The reason why I say this is because the phenotype is the physically noticeable characteristics in an organism, this allows them to mutate differently and only the ones who are fit enough and have the best phenotypes will survive.
Mitochondria - Within eukaryotic cells, mitochondria function somewhat like batteries, because they convert energy from one form to another: food nutrients to ATP.
