Easy. Answer is oxygen because it says which one was missing before any life was on earth. And in order to have life on earth you need oxygen!
:)
The answer is b. I am not sure exactly how to explain this, but it fits in much better with that question. I hope this could help you!
Answer:
Human insulin
Explanation:
The process where by region of a DNA that codes for a particular function is transferred between organisms into cells Is described as gene transfer. This process can be used to enhance the mechanism of producing a gene that is not originally present in such organisms before. Therefore if the gene that code for insulin is inserted into a bacterial vector , the offspring of such bacteria will be able to synthesize insulin in their cell
Answer:
A would be the correct answer I'm sure
Explanation:
Have a nice day
Genes and the environment can affect an organisms traits
